formal definition of critical thinking

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critical thinking

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• Stanford Encyclopedia of Philosophy - Critical Thinking
• Internet Encyclopedia of Philosophy - Critical Thinking
• Monash University - Student Academic Success - What is critical thinking?
• Oklahoma State University Pressbooks - Critical Thinking - Introduction to Critical Thinking
• University of Louisville - Critical Thinking

critical thinking , in educational theory, mode of cognition using deliberative reasoning and impartial scrutiny of information to arrive at a possible solution to a problem. From the perspective of educators, critical thinking encompasses both a set of logical skills that can be taught and a disposition toward reflective open inquiry that can be cultivated . The term critical thinking was coined by American philosopher and educator John Dewey in the book How We Think (1910) and was adopted by the progressive education movement as a core instructional goal that offered a dynamic modern alternative to traditional educational methods such as rote memorization.

Critical thinking is characterized by a broad set of related skills usually including the abilities to

• break down a problem into its constituent parts to reveal its underlying logic and assumptions
• recognize and account for one’s own biases in judgment and experience
• collect and assess relevant evidence from either personal observations and experimentation or by gathering external information
• adjust and reevaluate one’s own thinking in response to what one has learned
• form a reasoned assessment in order to propose a solution to a problem or a more accurate understanding of the topic at hand

Theorists have noted that such skills are only valuable insofar as a person is inclined to use them. Consequently, they emphasize that certain habits of mind are necessary components of critical thinking. This disposition may include curiosity, open-mindedness, self-awareness, empathy , and persistence.

Although there is a generally accepted set of qualities that are associated with critical thinking, scholarly writing about the term has highlighted disagreements over its exact definition and whether and how it differs from related concepts such as problem solving . In addition, some theorists have insisted that critical thinking be regarded and valued as a process and not as a goal-oriented skill set to be used to solve problems. Critical-thinking theory has also been accused of reflecting patriarchal assumptions about knowledge and ways of knowing that are inherently biased against women.

Dewey, who also used the term reflective thinking , connected critical thinking to a tradition of rational inquiry associated with modern science . From the turn of the 20th century, he and others working in the overlapping fields of psychology , philosophy , and educational theory sought to rigorously apply the scientific method to understand and define the process of thinking. They conceived critical thinking to be related to the scientific method but more open, flexible, and self-correcting; instead of a recipe or a series of steps, critical thinking would be a wider set of skills, patterns, and strategies that allow someone to reason through an intellectual topic, constantly reassessing assumptions and potential explanations in order to arrive at a sound judgment and understanding.

In the progressive education movement in the United States , critical thinking was seen as a crucial component of raising citizens in a democratic society. Instead of imparting a particular series of lessons or teaching only canonical subject matter, theorists thought that teachers should train students in how to think. As critical thinkers, such students would be equipped to be productive and engaged citizens who could cooperate and rationally overcome differences inherent in a pluralistic society.

Beginning in the 1970s and ’80s, critical thinking as a key outcome of school and university curriculum leapt to the forefront of U.S. education policy. In an atmosphere of renewed Cold War competition and amid reports of declining U.S. test scores, there were growing fears that the quality of education in the United States was falling and that students were unprepared. In response, a concerted effort was made to systematically define curriculum goals and implement standardized testing regimens , and critical-thinking skills were frequently included as a crucially important outcome of a successful education. A notable event in this movement was the release of the 1980 report of the Rockefeller Commission on the Humanities that called for the U.S. Department of Education to include critical thinking on its list of “basic skills.” Three years later the California State University system implemented a policy that required every undergraduate student to complete a course in critical thinking.

Critical thinking continued to be put forward as a central goal of education in the early 21st century. Its ubiquity in the language of education policy and in such guidelines as the Common Core State Standards in the United States generated some criticism that the concept itself was both overused and ill-defined. In addition, an argument was made by teachers, theorists, and others that educators were not being adequately trained to teach critical thinking.

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• What Is Critical Thinking? | Definition & Examples

What Is Critical Thinking? | Definition & Examples

Published on May 30, 2022 by Eoghan Ryan . Revised on May 31, 2023.

Critical thinking is the ability to effectively analyze information and form a judgment .

To think critically, you must be aware of your own biases and assumptions when encountering information, and apply consistent standards when evaluating sources .

Critical thinking skills help you to:

• Identify credible sources
• Evaluate and respond to arguments
• Assess alternative viewpoints
• Test hypotheses against relevant criteria

Table of contents

Why is critical thinking important, critical thinking examples, how to think critically, other interesting articles, frequently asked questions about critical thinking.

Critical thinking is important for making judgments about sources of information and forming your own arguments. It emphasizes a rational, objective, and self-aware approach that can help you to identify credible sources and strengthen your conclusions.

Critical thinking is important in all disciplines and throughout all stages of the research process . The types of evidence used in the sciences and in the humanities may differ, but critical thinking skills are relevant to both.

In academic writing , critical thinking can help you to determine whether a source:

• Is free from research bias
• Provides evidence to support its research findings
• Considers alternative viewpoints

Outside of academia, critical thinking goes hand in hand with information literacy to help you form opinions rationally and engage independently and critically with popular media.

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Critical thinking can help you to identify reliable sources of information that you can cite in your research paper . It can also guide your own research methods and inform your own arguments.

Outside of academia, critical thinking can help you to be aware of both your own and others’ biases and assumptions.

Academic examples

However, when you compare the findings of the study with other current research, you determine that the results seem improbable. You analyze the paper again, consulting the sources it cites.

You notice that the research was funded by the pharmaceutical company that created the treatment. Because of this, you view its results skeptically and determine that more independent research is necessary to confirm or refute them. Example: Poor critical thinking in an academic context You’re researching a paper on the impact wireless technology has had on developing countries that previously did not have large-scale communications infrastructure. You read an article that seems to confirm your hypothesis: the impact is mainly positive. Rather than evaluating the research methodology, you accept the findings uncritically.

Nonacademic examples

However, you decide to compare this review article with consumer reviews on a different site. You find that these reviews are not as positive. Some customers have had problems installing the alarm, and some have noted that it activates for no apparent reason.

You revisit the original review article. You notice that the words “sponsored content” appear in small print under the article title. Based on this, you conclude that the review is advertising and is therefore not an unbiased source. Example: Poor critical thinking in a nonacademic context You support a candidate in an upcoming election. You visit an online news site affiliated with their political party and read an article that criticizes their opponent. The article claims that the opponent is inexperienced in politics. You accept this without evidence, because it fits your preconceptions about the opponent.

There is no single way to think critically. How you engage with information will depend on the type of source you’re using and the information you need.

However, you can engage with sources in a systematic and critical way by asking certain questions when you encounter information. Like the CRAAP test , these questions focus on the currency , relevance , authority , accuracy , and purpose of a source of information.

When encountering information, ask:

• Who is the author? Are they an expert in their field?
• What do they say? Is their argument clear? Can you summarize it?
• When did they say this? Is the source current?
• Where is the information published? Is it an academic article? Is it peer-reviewed ?
• Why did the author publish it? What is their motivation?
• How do they make their argument? Is it backed up by evidence? Does it rely on opinion, speculation, or appeals to emotion ? Do they address alternative arguments?

Critical thinking also involves being aware of your own biases, not only those of others. When you make an argument or draw your own conclusions, you can ask similar questions about your own writing:

• Am I only considering evidence that supports my preconceptions?
• Is my argument expressed clearly and backed up with credible sources?
• Would I be convinced by this argument coming from someone else?

If you want to know more about ChatGPT, AI tools , citation , and plagiarism , make sure to check out some of our other articles with explanations and examples.

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• Using ChatGPT for your studies
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• Chicago style
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Critical thinking refers to the ability to evaluate information and to be aware of biases or assumptions, including your own.

Like information literacy , it involves evaluating arguments, identifying and solving problems in an objective and systematic way, and clearly communicating your ideas.

Critical thinking skills include the ability to:

You can assess information and arguments critically by asking certain questions about the source. You can use the CRAAP test , focusing on the currency , relevance , authority , accuracy , and purpose of a source of information.

Ask questions such as:

• Who is the author? Are they an expert?
• How do they make their argument? Is it backed up by evidence?

A credible source should pass the CRAAP test  and follow these guidelines:

• The information should be up to date and current.
• The author and publication should be a trusted authority on the subject you are researching.
• The sources the author cited should be easy to find, clear, and unbiased.
• For a web source, the URL and layout should signify that it is trustworthy.

Information literacy refers to a broad range of skills, including the ability to find, evaluate, and use sources of information effectively.

Being information literate means that you:

• Know how to find credible sources
• Use relevant sources to inform your research
• Understand what constitutes plagiarism
• Know how to cite your sources correctly

Confirmation bias is the tendency to search, interpret, and recall information in a way that aligns with our pre-existing values, opinions, or beliefs. It refers to the ability to recollect information best when it amplifies what we already believe. Relatedly, we tend to forget information that contradicts our opinions.

Although selective recall is a component of confirmation bias, it should not be confused with recall bias.

On the other hand, recall bias refers to the differences in the ability between study participants to recall past events when self-reporting is used. This difference in accuracy or completeness of recollection is not related to beliefs or opinions. Rather, recall bias relates to other factors, such as the length of the recall period, age, and the characteristics of the disease under investigation.

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critical thinking

Definition of critical thinking

Examples of critical thinking in a sentence.

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'critical thinking.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

1815, in the meaning defined at sense 1

Dictionary Entries Near critical thinking

critical temperature

critical value

Cite this Entry

“Critical thinking.” Merriam-Webster.com Dictionary , Merriam-Webster, https://www.merriam-webster.com/dictionary/critical%20thinking. Accessed 16 Sep. 2024.

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Our Concept and Definition of Critical Thinking

Critical Thinking in Reading and Composition

Glossary of Grammatical and Rhetorical Terms

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• An Introduction to Punctuation
• Ph.D., Rhetoric and English, University of Georgia
• M.A., Modern English and American Literature, University of Leicester
• B.A., English, State University of New York

Critical thinking is the process of independently analyzing, synthesizing, and evaluating information as a guide to behavior and beliefs.

The American Philosophical Association has defined critical thinking as "the process of purposeful, self-regulatory judgment. The process gives reasoned consideration to evidence , contexts , conceptualizations, methods, and criteria" (1990). Critical thinking is sometimes broadly defined as "thinking about thinking."

Critical thinking skills include the ability to interpret, verify, and reason, all of which involve applying the principles of logic . The process of using critical thinking to guide writing is called critical writing .

Observations

• " Critical Thinking is essential as a tool of inquiry. As such, Critical Thinking is a liberating force in education and a powerful resource in one’s personal and civic life. While not synonymous with good thinking, Critical Thinking is a pervasive and self-rectifying human phenomenon. The ideal critical thinker is habitually inquisitive, well-informed, trustful of reason, open-minded, flexible, fair-minded in evaluation, honest in facing personal biases, prudent in making judgments, willing to reconsider, clear about issues, orderly in complex matters, diligent in seeking relevant information, reasonable in the selection of criteria, focused in inquiry, and persistent in seeking results which are as precise as the subject and the circumstances of inquiry permit." (American Philosophical Association, "Consensus Statement Regarding Critical Thinking," 1990)
• Thought and Language "In order to understand reasoning [...], it is necessary to pay careful attention to the relationship between thought and language . The relationship seems to be straightforward: thought is expressed in and through language. But this claim, while true, is an oversimplification. People often fail to say what they mean. Everyone has had the experience of having their \ misunderstood by others. And we all use words not merely to express our thoughts but also to shape them. Developing our critical thinking skills, therefore, requires an understanding of the ways in which words can (and often fail to) express our thoughts." (William Hughes and Jonathan Lavery, Critical Thinking: An Introduction to the Basic Skills , 4th ed. Broadview, 2004)
• Dispositions That Foster or Impede Critical thinking "Dispositions that foster critical thinking include [a] facility in perceiving irony , ambiguity , and multiplicity of meanings or points of view; the development of open-mindedness, autonomous thought, and reciprocity (Piaget's term for the ability to empathize with other individuals, social groups, nationalities, ideologies, etc.). Dispositions that act as impediments to critical thinking include defense mechanisms (such as absolutism or primary certitude, denial, projection), culturally conditioned assumptions, authoritarianism, egocentrism, and ethnocentrism, rationalization, compartmentalization, stereotyping and prejudice." (Donald Lazere, "Invention, Critical Thinking, and the Analysis of Political Rhetoric." Perspectives on Rhetorical Invention , ed. by Janet M. Atwill and Janice M. Lauer. University of Tennessee Press, 2002)
• Critical Thinking and Composing - "[T]he most intensive and demanding tool for eliciting sustained critical thought is a well-designed writing assignment on a subject matter problem. The underlying premise is that writing is closely linked with thinking and that in presenting students with significant problems to write about—and in creating an environment that demands their best writing—we can promote their general cognitive and intellectual growth. When we make students struggle with their writing, we are making them struggle with thought itself. Emphasizing writing and critical thinking , therefore, generally increases the academic rigor of a course. Often the struggle of writing, linked as it is to the struggle of thinking and to the growth of a person's intellectual powers, awakens students to the real nature of learning." (John C. Bean,  Engaging Ideas: The Professor's Guide to Integrating Writing, Critical Thinking, and Active Learning in the Classroom , 2nd ed. Wiley, 2011) - "Finding a fresh approach to a writing assignment means that you must see the subject without the blinders of preconception. When people expect to see a thing in a certain way, it usually appears that way, whether or not that is its true image. Similarly, thinking based on prefabricated ideas produces writing that says nothing new, that offers nothing important to the reader. As a writer, you have a responsibility to go beyond the expected views and present your subject so that the reader sees it with fresh eyes. . . . [C]ritical thinking is a fairly systematic method of defining a problem and synthesizing knowledge about it, thereby creating the perspective you need to develop new ideas. . . . " Classical rhetoricians used a series of three questions to help focus an argument . Today these questions can still help writers understand the topic about which they are writing. An sit? (Is the problem a fact?); Quid sit (What is the definition of the problem?); and Quale sit? (What kind of problem is it?). By asking these questions, writers see their subject from many new angles before they begin to narrow the focus to one particular aspect." (Kristin R. Woolever, About Writing: A Rhetoric for Advanced Writers . Wadsworth, 1991)

Logical Fallacies

Ad Misericordiam

Appeal to Authority

Appeal to Force

Appeal to Humor

Appeal to Ignorance

Appeal to the People

Begging the Question

Circular Argument

Complex Question

Contradictory Premises

Dicto Simpliciter , Equivocation

False Analogy

False Dilemma

Gambler's Fallacy

Hasty Generalization

Name-Calling

Non Sequitur

Poisoning the Well

Red Herring

Slippery Slope

Stacking the Deck

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Introduction to Logic and Critical Thinking

(10 reviews)

Matthew Van Cleave, Lansing Community College

Copyright Year: 2016

Publisher: Matthew J. Van Cleave

Language: English

Formats Available

Conditions of use.

Learn more about reviews.

Reviewed by "yusef" Alexander Hayes, Professor, North Shore Community College on 6/9/21

Formal and informal reasoning, argument structure, and fallacies are covered comprehensively, meeting the author's goal of both depth and succinctness. read more

Comprehensiveness rating: 5 see less

Formal and informal reasoning, argument structure, and fallacies are covered comprehensively, meeting the author's goal of both depth and succinctness.

Content Accuracy rating: 5

The book is accurate.

Relevance/Longevity rating: 5

While many modern examples are used, and they are helpful, they are not necessarily needed. The usefulness of logical principles and skills have proved themselves, and this text presents them clearly with many examples.

Clarity rating: 5

It is obvious that the author cares about their subject, audience, and students. The text is comprehensible and interesting.

Consistency rating: 5

The format is easy to understand and is consistent in framing.

Modularity rating: 5

This text would be easy to adapt.

Organization/Structure/Flow rating: 5

The organization is excellent, my one suggestion would be a concluding chapter.

Interface rating: 5

I accessed the PDF version and it would be easy to work with.

Grammatical Errors rating: 5

The writing is excellent.

Cultural Relevance rating: 5

This is not an offensive text.

Reviewed by Susan Rottmann, Part-time Lecturer, University of Southern Maine on 3/2/21

I reviewed this book for a course titled "Creative and Critical Inquiry into Modern Life." It won't meet all my needs for that course, but I haven't yet found a book that would. I wanted to review this one because it states in the preface that it... read more

Comprehensiveness rating: 4 see less

I reviewed this book for a course titled "Creative and Critical Inquiry into Modern Life." It won't meet all my needs for that course, but I haven't yet found a book that would. I wanted to review this one because it states in the preface that it fits better for a general critical thinking course than for a true logic course. I'm not sure that I'd agree. I have been using Browne and Keeley's "Asking the Right Questions: A Guide to Critical Thinking," and I think that book is a better introduction to critical thinking for non-philosophy majors. However, the latter is not open source so I will figure out how to get by without it in the future. Overall, the book seems comprehensive if the subject is logic. The index is on the short-side, but fine. However, one issue for me is that there are no page numbers on the table of contents, which is pretty annoying if you want to locate particular sections.

Content Accuracy rating: 4

I didn't find any errors. In general the book uses great examples. However, they are very much based in the American context, not for an international student audience. Some effort to broaden the chosen examples would make the book more widely applicable.

Relevance/Longevity rating: 4

I think the book will remain relevant because of the nature of the material that it addresses, however there will be a need to modify the examples in future editions and as the social and political context changes.

Clarity rating: 3

The text is lucid, but I think it would be difficult for introductory-level students who are not philosophy majors. For example, in Browne and Keeley's "Asking the Right Questions: A Guide to Critical Thinking," the sub-headings are very accessible, such as "Experts cannot rescue us, despite what they say" or "wishful thinking: perhaps the biggest single speed bump on the road to critical thinking." By contrast, Van Cleave's "Introduction to Logic and Critical Thinking" has more subheadings like this: "Using your own paraphrases of premises and conclusions to reconstruct arguments in standard form" or "Propositional logic and the four basic truth functional connectives." If students are prepared very well for the subject, it would work fine, but for students who are newly being introduced to critical thinking, it is rather technical.

It seems to be very consistent in terms of its terminology and framework.

Modularity rating: 4

The book is divided into 4 chapters, each having many sub-chapters. In that sense, it is readily divisible and modular. However, as noted above, there are no page numbers on the table of contents, which would make assigning certain parts rather frustrating. Also, I'm not sure why the book is only four chapter and has so many subheadings (for instance 17 in Chapter 2) and a length of 242 pages. Wouldn't it make more sense to break up the book into shorter chapters? I think this would make it easier to read and to assign in specific blocks to students.

Organization/Structure/Flow rating: 4

The organization of the book is fine overall, although I think adding page numbers to the table of contents and breaking it up into more separate chapters would help it to be more easily navigable.

Interface rating: 4

The book is very simply presented. In my opinion it is actually too simple. There are few boxes or diagrams that highlight and explain important points.

The text seems fine grammatically. I didn't notice any errors.

The book is written with an American audience in mind, but I did not notice culturally insensitive or offensive parts.

Overall, this book is not for my course, but I think it could work well in a philosophy course.

Reviewed by Daniel Lee, Assistant Professor of Economics and Leadership, Sweet Briar College on 11/11/19

This textbook is not particularly comprehensive (4 chapters long), but I view that as a benefit. In fact, I recommend it for use outside of traditional logic classes, but rather interdisciplinary classes that evaluate argument read more

Comprehensiveness rating: 3 see less

This textbook is not particularly comprehensive (4 chapters long), but I view that as a benefit. In fact, I recommend it for use outside of traditional logic classes, but rather interdisciplinary classes that evaluate argument

To the best of my ability, I regard this content as accurate, error-free, and unbiased

The book is broadly relevant and up-to-date, with a few stray temporal references (sydney olympics, particular presidencies). I don't view these time-dated examples as problematic as the logical underpinnings are still there and easily assessed

Clarity rating: 4

My only pushback on clarity is I didn't find the distinction between argument and explanation particularly helpful/useful/easy to follow. However, this experience may have been unique to my class.

To the best of my ability, I regard this content as internally consistent

I found this text quite modular, and was easily able to integrate other texts into my lessons and disregard certain chapters or sub-sections

The book had a logical and consistent structure, but to the extent that there are only 4 chapters, there isn't much scope for alternative approaches here

No problems with the book's interface

The text is grammatically sound

Cultural Relevance rating: 4

Perhaps the text could have been more universal in its approach. While I didn't find the book insensitive per-se, logic can be tricky here because the point is to evaluate meaningful (non-trivial) arguments, but any argument with that sense of gravity can also be traumatic to students (abortion, death penalty, etc)

No additional comments

Reviewed by Lisa N. Thomas-Smith, Graduate Part-time Instructor, CU Boulder on 7/1/19

The text covers all the relevant technical aspects of introductory logic and critical thinking, and covers them well. A separate glossary would be quite helpful to students. However, the terms are clearly and thoroughly explained within the text,... read more

The text covers all the relevant technical aspects of introductory logic and critical thinking, and covers them well. A separate glossary would be quite helpful to students. However, the terms are clearly and thoroughly explained within the text, and the index is very thorough.

The content is excellent. The text is thorough and accurate with no errors that I could discern. The terminology and exercises cover the material nicely and without bias.

The text should easily stand the test of time. The exercises are excellent and would be very helpful for students to internalize correct critical thinking practices. Because of the logical arrangement of the text and the many sub-sections, additional material should be very easy to add.

The text is extremely clearly and simply written. I anticipate that a diligent student could learn all of the material in the text with little additional instruction. The examples are relevant and easy to follow.

The text did not confuse terms or use inconsistent terminology, which is very important in a logic text. The discipline often uses multiple terms for the same concept, but this text avoids that trap nicely.

The text is fairly easily divisible. Since there are only four chapters, those chapters include large blocks of information. However, the chapters themselves are very well delineated and could be easily broken up so that parts could be left out or covered in a different order from the text.

The flow of the text is excellent. All of the information is handled solidly in an order that allows the student to build on the information previously covered.

The PDF Table of Contents does not include links or page numbers which would be very helpful for navigation. Other than that, the text was very easy to navigate. All the images, charts, and graphs were very clear

I found no grammatical errors in the text.

Cultural Relevance rating: 3

The text including examples and exercises did not seem to be offensive or insensitive in any specific way. However, the examples included references to black and white people, but few others. Also, the text is very American specific with many examples from and for an American audience. More diversity, especially in the examples, would be appropriate and appreciated.

Reviewed by Leslie Aarons, Associate Professor of Philosophy, CUNY LaGuardia Community College on 5/16/19

This is an excellent introductory (first-year) Logic and Critical Thinking textbook. The book covers the important elementary information, clearly discussing such things as the purpose and basic structure of an argument; the difference between an... read more

This is an excellent introductory (first-year) Logic and Critical Thinking textbook. The book covers the important elementary information, clearly discussing such things as the purpose and basic structure of an argument; the difference between an argument and an explanation; validity; soundness; and the distinctions between an inductive and a deductive argument in accessible terms in the first chapter. It also does a good job introducing and discussing informal fallacies (Chapter 4). The incorporation of opportunities to evaluate real-world arguments is also very effective. Chapter 2 also covers a number of formal methods of evaluating arguments, such as Venn Diagrams and Propositional logic and the four basic truth functional connectives, but to my mind, it is much more thorough in its treatment of Informal Logic and Critical Thinking skills, than it is of formal logic. I also appreciated that Van Cleave’s book includes exercises with answers and an index, but there is no glossary; which I personally do not find detracts from the book's comprehensiveness.

Overall, Van Cleave's book is error-free and unbiased. The language used is accessible and engaging. There were no glaring inaccuracies that I was able to detect.

Van Cleave's Textbook uses relevant, contemporary content that will stand the test of time, at least for the next few years. Although some examples use certain subjects like former President Obama, it does so in a useful manner that inspires the use of critical thinking skills. There are an abundance of examples that inspire students to look at issues from many different political viewpoints, challenging students to practice evaluating arguments, and identifying fallacies. Many of these exercises encourage students to critique issues, and recognize their own inherent reader-biases and challenge their own beliefs--hallmarks of critical thinking.

As mentioned previously, the author has an accessible style that makes the content relatively easy to read and engaging. He also does a suitable job explaining jargon/technical language that is introduced in the textbook.

Van Cleave uses terminology consistently and the chapters flow well. The textbook orients the reader by offering effective introductions to new material, step-by-step explanations of the material, as well as offering clear summaries of each lesson.

This textbook's modularity is really quite good. Its language and structure are not overly convoluted or too-lengthy, making it convenient for individual instructors to adapt the materials to suit their methodological preferences.

The topics in the textbook are presented in a logical and clear fashion. The structure of the chapters are such that it is not necessary to have to follow the chapters in their sequential order, and coverage of material can be adapted to individual instructor's preferences.

The textbook is free of any problematic interface issues. Topics, sections and specific content are accessible and easy to navigate. Overall it is user-friendly.

I did not find any significant grammatical issues with the textbook.

The textbook is not culturally insensitive, making use of a diversity of inclusive examples. Materials are especially effective for first-year critical thinking/logic students.

I intend to adopt Van Cleave's textbook for a Critical Thinking class I am teaching at the Community College level. I believe that it will help me facilitate student-learning, and will be a good resource to build additional classroom activities from the materials it provides.

Reviewed by Jennie Harrop, Chair, Department of Professional Studies, George Fox University on 3/27/18

While the book is admirably comprehensive, its extensive details within a few short chapters may feel overwhelming to students. The author tackles an impressive breadth of concepts in Chapter 1, 2, 3, and 4, which leads to 50-plus-page chapters... read more

While the book is admirably comprehensive, its extensive details within a few short chapters may feel overwhelming to students. The author tackles an impressive breadth of concepts in Chapter 1, 2, 3, and 4, which leads to 50-plus-page chapters that are dense with statistical analyses and critical vocabulary. These topics are likely better broached in manageable snippets rather than hefty single chapters.

The ideas addressed in Introduction to Logic and Critical Thinking are accurate but at times notably political. While politics are effectively used to exemplify key concepts, some students may be distracted by distinct political leanings.

The terms and definitions included are relevant, but the examples are specific to the current political, cultural, and social climates, which could make the materials seem dated in a few years without intentional and consistent updates.

While the reasoning is accurate, the author tends to complicate rather than simplify -- perhaps in an effort to cover a spectrum of related concepts. Beginning readers are likely to be overwhelmed and under-encouraged by his approach.

Consistency rating: 3

The four chapters are somewhat consistent in their play of definition, explanation, and example, but the structure of each chapter varies according to the concepts covered. In the third chapter, for example, key ideas are divided into sub-topics numbering from 3.1 to 3.10. In the fourth chapter, the sub-divisions are further divided into sub-sections numbered 4.1.1-4.1.5, 4.2.1-4.2.2, and 4.3.1 to 4.3.6. Readers who are working quickly to master new concepts may find themselves mired in similarly numbered subheadings, longing for a grounded concepts on which to hinge other key principles.

Modularity rating: 3

The book's four chapters make it mostly self-referential. The author would do well to beak this text down into additional subsections, easing readers' accessibility.

The content of the book flows logically and well, but the information needs to be better sub-divided within each larger chapter, easing the student experience.

The book's interface is effective, allowing readers to move from one section to the next with a single click. Additional sub-sections would ease this interplay even further.

Grammatical Errors rating: 4

Some minor errors throughout.

For the most part, the book is culturally neutral, avoiding direct cultural references in an effort to remain relevant.

Reviewed by Yoichi Ishida, Assistant Professor of Philosophy, Ohio University on 2/1/18

This textbook covers enough topics for a first-year course on logic and critical thinking. Chapter 1 covers the basics as in any standard textbook in this area. Chapter 2 covers propositional logic and categorical logic. In propositional logic,... read more

This textbook covers enough topics for a first-year course on logic and critical thinking. Chapter 1 covers the basics as in any standard textbook in this area. Chapter 2 covers propositional logic and categorical logic. In propositional logic, this textbook does not cover suppositional arguments, such as conditional proof and reductio ad absurdum. But other standard argument forms are covered. Chapter 3 covers inductive logic, and here this textbook introduces probability and its relationship with cognitive biases, which are rarely discussed in other textbooks. Chapter 4 introduces common informal fallacies. The answers to all the exercises are given at the end. However, the last set of exercises is in Chapter 3, Section 5. There are no exercises in the rest of the chapter. Chapter 4 has no exercises either. There is index, but no glossary.

The textbook is accurate.

The content of this textbook will not become obsolete soon.

The textbook is written clearly.

The textbook is internally consistent.

The textbook is fairly modular. For example, Chapter 3, together with a few sections from Chapter 1, can be used as a short introduction to inductive logic.

The textbook is well-organized.

There are no interface issues.

I did not find any grammatical errors.

This textbook is relevant to a first semester logic or critical thinking course.

Reviewed by Payal Doctor, Associate Professro, LaGuardia Community College on 2/1/18

This text is a beginner textbook for arguments and propositional logic. It covers the basics of identifying arguments, building arguments, and using basic logic to construct propositions and arguments. It is quite comprehensive for a beginner... read more

This text is a beginner textbook for arguments and propositional logic. It covers the basics of identifying arguments, building arguments, and using basic logic to construct propositions and arguments. It is quite comprehensive for a beginner book, but seems to be a good text for a course that needs a foundation for arguments. There are exercises on creating truth tables and proofs, so it could work as a logic primer in short sessions or with the addition of other course content.

The books is accurate in the information it presents. It does not contain errors and is unbiased. It covers the essential vocabulary clearly and givens ample examples and exercises to ensure the student understands the concepts

The content of the book is up to date and can be easily updated. Some examples are very current for analyzing the argument structure in a speech, but for this sort of text understandable examples are important and the author uses good examples.

The book is clear and easy to read. In particular, this is a good text for community college students who often have difficulty with reading comprehension. The language is straightforward and concepts are well explained.

The book is consistent in terminology, formatting, and examples. It flows well from one topic to the next, but it is also possible to jump around the text without loosing the voice of the text.

The books is broken down into sub units that make it easy to assign short blocks of content at a time. Later in the text, it does refer to a few concepts that appear early in that text, but these are all basic concepts that must be used to create a clear and understandable text. No sections are too long and each section stays on topic and relates the topic to those that have come before when necessary.

The flow of the text is logical and clear. It begins with the basic building blocks of arguments, and practice identifying more and more complex arguments is offered. Each chapter builds up from the previous chapter in introducing propositional logic, truth tables, and logical arguments. A select number of fallacies are presented at the end of the text, but these are related to topics that were presented before, so it makes sense to have these last.

The text is free if interface issues. I used the PDF and it worked fine on various devices without loosing formatting.

1. The book contains no grammatical errors.

The text is culturally sensitive, but examples used are a bit odd and may be objectionable to some students. For instance, President Obama's speech on Syria is used to evaluate an extended argument. This is an excellent example and it is explained well, but some who disagree with Obama's policies may have trouble moving beyond their own politics. However, other examples look at issues from all political viewpoints and ask students to evaluate the argument, fallacy, etc. and work towards looking past their own beliefs. Overall this book does use a variety of examples that most students can understand and evaluate.

My favorite part of this book is that it seems to be written for community college students. My students have trouble understanding readings in the New York Times, so it is nice to see a logic and critical thinking text use real language that students can understand and follow without the constant need of a dictionary.

Reviewed by Rebecca Owen, Adjunct Professor, Writing, Chemeketa Community College on 6/20/17

This textbook is quite thorough--there are conversational explanations of argument structure and logic. I think students will be happy with the conversational style this author employs. Also, there are many examples and exercises using current... read more

This textbook is quite thorough--there are conversational explanations of argument structure and logic. I think students will be happy with the conversational style this author employs. Also, there are many examples and exercises using current events, funny scenarios, or other interesting ways to evaluate argument structure and validity. The third section, which deals with logical fallacies, is very clear and comprehensive. My only critique of the material included in the book is that the middle section may be a bit dense and math-oriented for learners who appreciate the more informal, informative style of the first and third section. Also, the book ends rather abruptly--it moves from a description of a logical fallacy to the answers for the exercises earlier in the text.

The content is very reader-friendly, and the author writes with authority and clarity throughout the text. There are a few surface-level typos (Starbuck's instead of Starbucks, etc.). None of these small errors detract from the quality of the content, though.

One thing I really liked about this text was the author's wide variety of examples. To demonstrate different facets of logic, he used examples from current media, movies, literature, and many other concepts that students would recognize from their daily lives. The exercises in this text also included these types of pop-culture references, and I think students will enjoy the familiarity--as well as being able to see the logical structures behind these types of references. I don't think the text will need to be updated to reflect new instances and occurrences; the author did a fine job at picking examples that are relatively timeless. As far as the subject matter itself, I don't think it will become obsolete any time soon.

The author writes in a very conversational, easy-to-read manner. The examples used are quite helpful. The third section on logical fallacies is quite easy to read, follow, and understand. A student in an argument writing class could benefit from this section of the book. The middle section is less clear, though. A student learning about the basics of logic might have a hard time digesting all of the information contained in chapter two. This material might be better in two separate chapters. I think the author loses the balance of a conversational, helpful tone and focuses too heavily on equations.

Consistency rating: 4

Terminology in this book is quite consistent--the key words are highlighted in bold. Chapters 1 and 3 follow a similar organizational pattern, but chapter 2 is where the material becomes more dense and equation-heavy. I also would have liked a closing passage--something to indicate to the reader that we've reached the end of the chapter as well as the book.

I liked the overall structure of this book. If I'm teaching an argumentative writing class, I could easily point the students to the chapters where they can identify and practice identifying fallacies, for instance. The opening chapter is clear in defining the necessary terms, and it gives the students an understanding of the toolbox available to them in assessing and evaluating arguments. Even though I found the middle section to be dense, smaller portions could be assigned.

The author does a fine job connecting each defined term to the next. He provides examples of how each defined term works in a sentence or in an argument, and then he provides practice activities for students to try. The answers for each question are listed in the final pages of the book. The middle section feels like the heaviest part of the whole book--it would take the longest time for a student to digest if assigned the whole chapter. Even though this middle section is a bit heavy, it does fit the overall structure and flow of the book. New material builds on previous chapters and sub-chapters. It ends abruptly--I didn't realize that it had ended, and all of a sudden I found myself in the answer section for those earlier exercises.

The simple layout is quite helpful! There is nothing distracting, image-wise, in this text. The table of contents is clearly arranged, and each topic is easy to find.

Tiny edits could be made (Starbuck's/Starbucks, for one). Otherwise, it is free of distracting grammatical errors.

This text is quite culturally relevant. For instance, there is one example that mentions the rumors of Barack Obama's birthplace as somewhere other than the United States. This example is used to explain how to analyze an argument for validity. The more "sensational" examples (like the Obama one above) are helpful in showing argument structure, and they can also help students see how rumors like this might gain traction--as well as help to show students how to debunk them with their newfound understanding of argument and logic.

The writing style is excellent for the subject matter, especially in the third section explaining logical fallacies. Thank you for the opportunity to read and review this text!

Reviewed by Laurel Panser, Instructor, Riverland Community College on 6/20/17

This is a review of Introduction to Logic and Critical Thinking, an open source book version 1.4 by Matthew Van Cleave. The comparison book used was Patrick J. Hurley’s A Concise Introduction to Logic 12th Edition published by Cengage as well as... read more

This is a review of Introduction to Logic and Critical Thinking, an open source book version 1.4 by Matthew Van Cleave. The comparison book used was Patrick J. Hurley’s A Concise Introduction to Logic 12th Edition published by Cengage as well as the 13th edition with the same title. Lori Watson is the second author on the 13th edition.

Competing with Hurley is difficult with respect to comprehensiveness. For example, Van Cleave’s book is comprehensive to the extent that it probably covers at least two-thirds or more of what is dealt with in most introductory, one-semester logic courses. Van Cleave’s chapter 1 provides an overview of argumentation including discerning non-arguments from arguments, premises versus conclusions, deductive from inductive arguments, validity, soundness and more. Much of Van Cleave’s chapter 1 parallel’s Hurley’s chapter 1. Hurley’s chapter 3 regarding informal fallacies is comprehensive while Van Cleave’s chapter 4 on this topic is less extensive. Categorical propositions are a topic in Van Cleave’s chapter 2; Hurley’s chapters 4 and 5 provide more instruction on this, however. Propositional logic is another topic in Van Cleave’s chapter 2; Hurley’s chapters 6 and 7 provide more information on this, though. Van Cleave did discuss messy issues of language meaning briefly in his chapter 1; that is the topic of Hurley’s chapter 2.

Van Cleave’s book includes exercises with answers and an index. A glossary was not included.

Reviews of open source textbooks typically include criteria besides comprehensiveness. These include comments on accuracy of the information, whether the book will become obsolete soon, jargon-free clarity to the extent that is possible, organization, navigation ease, freedom from grammar errors and cultural relevance; Van Cleave’s book is fine in all of these areas. Further criteria for open source books includes modularity and consistency of terminology. Modularity is defined as including blocks of learning material that are easy to assign to students. Hurley’s book has a greater degree of modularity than Van Cleave’s textbook. The prose Van Cleave used is consistent.

Van Cleave’s book will not become obsolete soon.

Van Cleave’s book has accessible prose.

Van Cleave used terminology consistently.

Van Cleave’s book has a reasonable degree of modularity.

Van Cleave’s book is organized. The structure and flow of his book is fine.

Problems with navigation are not present.

Grammar problems were not present.

Van Cleave’s book is culturally relevant.

Van Cleave’s book is appropriate for some first semester logic courses.

Table of Contents

Chapter 1: Reconstructing and analyzing arguments

• 1.1 What is an argument?
• 1.2 Identifying arguments
• 1.3 Arguments vs. explanations
• 1.4 More complex argument structures
• 1.5 Using your own paraphrases of premises and conclusions to reconstruct arguments in standard form
• 1.6 Validity
• 1.7 Soundness
• 1.8 Deductive vs. inductive arguments
• 1.9 Arguments with missing premises
• 1.10 Assuring, guarding, and discounting
• 1.11 Evaluative language
• 1.12 Evaluating a real-life argument

Chapter 2: Formal methods of evaluating arguments

• 2.1 What is a formal method of evaluation and why do we need them?
• 2.2 Propositional logic and the four basic truth functional connectives
• 2.3 Negation and disjunction
• 2.4 Using parentheses to translate complex sentences
• 2.5 “Not both” and “neither nor”
• 2.6 The truth table test of validity
• 2.7 Conditionals
• 2.8 “Unless”
• 2.9 Material equivalence
• 2.10 Tautologies, contradictions, and contingent statements
• 2.11 Proofs and the 8 valid forms of inference
• 2.12 How to construct proofs
• 2.13 Short review of propositional logic
• 2.14 Categorical logic
• 2.15 The Venn test of validity for immediate categorical inferences
• 2.16 Universal statements and existential commitment
• 2.17 Venn validity for categorical syllogisms

Chapter 3: Evaluating inductive arguments and probabilistic and statistical fallacies

• 3.1 Inductive arguments and statistical generalizations
• 3.2 Inference to the best explanation and the seven explanatory virtues
• 3.3 Analogical arguments
• 3.4 Causal arguments
• 3.5 Probability
• 3.6 The conjunction fallacy
• 3.7 The base rate fallacy
• 3.8 The small numbers fallacy
• 3.9 Regression to the mean fallacy
• 3.10 Gambler's fallacy

Chapter 4: Informal fallacies

• 4.1 Formal vs. informal fallacies
• 4.1.1 Composition fallacy
• 4.1.2 Division fallacy
• 4.1.3 Begging the question fallacy
• 4.1.4 False dichotomy
• 4.1.5 Equivocation
• 4.2 Slippery slope fallacies
• 4.2.1 Conceptual slippery slope
• 4.2.2 Causal slippery slope
• 4.3 Fallacies of relevance
• 4.3.1 Ad hominem
• 4.3.2 Straw man
• 4.3.3 Tu quoque
• 4.3.4 Genetic
• 4.3.5 Appeal to consequences
• 4.3.6 Appeal to authority

Answers to exercises Glossary/Index

Ancillary Material

About the book.

This is an introductory textbook in logic and critical thinking. The goal of the textbook is to provide the reader with a set of tools and skills that will enable them to identify and evaluate arguments. The book is intended for an introductory course that covers both formal and informal logic. As such, it is not a formal logic textbook, but is closer to what one would find marketed as a “critical thinking textbook.”

About the Contributors

Matthew Van Cleave ,   PhD, Philosophy, University of Cincinnati, 2007.  VAP at Concordia College (Moorhead), 2008-2012.  Assistant Professor at Lansing Community College, 2012-2016. Professor at Lansing Community College, 2016-

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PHIL102: Introduction to Critical Thinking and Logic

Course introduction.

• Time: 40 hours
• College Credit Recommended ($25 Proctor Fee) -->
• Free Certificate

The course touches upon a wide range of reasoning skills, from verbal argument analysis to formal logic, visual and statistical reasoning, scientific methodology, and creative thinking. Mastering these skills will help you become a more perceptive reader and listener, a more persuasive writer and presenter, and a more effective researcher and scientist.

The first unit introduces the terrain of critical thinking and covers the basics of meaning analysis, while the second unit provides a primer for analyzing arguments. All of the material in these first units will be built upon in subsequent units, which cover informal and formal logic, Venn diagrams, scientific reasoning, and strategic and creative thinking.

Course Syllabus

First, read the course syllabus. Then, enroll in the course by clicking "Enroll me". Click Unit 1 to read its introduction and learning outcomes. You will then see the learning materials and instructions on how to use them.

Unit 1: Introduction and Meaning Analysis

Critical thinking is a broad classification for a diverse array of reasoning techniques. In general, critical thinking works by breaking arguments and claims down to their basic underlying structure so we can see them clearly and determine whether they are rational. The idea is to help us do a better job of understanding and evaluating what we read, what we hear, and what we write and say.

In this unit, we will define the broad contours of critical thinking and learn why it is a valuable and useful object of study. We will also introduce the fundamentals of meaning analysis: the difference between literal meaning and implication, the principles of definition, how to identify when a disagreement is merely verbal, the distinction between necessary and sufficient conditions, and problems with the imprecision of ordinary language.

Completing this unit should take you approximately 5 hours.

Unit 2: Argument Analysis

Arguments are the fundamental components of all rational discourse: nearly everything we read and write, like scientific reports, newspaper columns, and personal letters, as well as most of our verbal conversations, contain arguments. Picking the arguments out from the rest of our often convoluted discourse can be difficult. Once we have identified an argument, we still need to determine whether or not it is sound. Luckily, arguments obey a set of formal rules that we can use to determine whether they are good or bad.

In this unit, you will learn how to identify arguments, what makes an argument sound as opposed to unsound or merely valid, the difference between deductive and inductive reasoning, and how to map arguments to reveal their structure.

Completing this unit should take you approximately 7 hours.

Unit 3: Basic Sentential Logic

This unit introduces a topic that many students find intimidating: formal logic. Although it sounds difficult and complicated, formal (or symbolic) logic is actually a fairly straightforward way of revealing the structure of reasoning. By translating arguments into symbols, you can more readily see what is right and wrong with them and learn how to formulate better arguments. Advanced courses in formal logic focus on using rules of inference to construct elaborate proofs. Using these techniques, you can solve many complicated problems simply by manipulating symbols on the page. In this course, however, you will only be looking at the most basic properties of a system of logic. In this unit, you will learn how to turn phrases in ordinary language into well-formed formulas, draw truth tables for formulas, and evaluate arguments using those truth tables.

Completing this unit should take you approximately 13 hours.

Unit 4: Venn Diagrams

In addition to using predicate logic, the limitations of sentential logic can also be overcome by using Venn diagrams to illustrate statements and arguments. Statements that include general words like "some" or "few" as well as absolute words like "every" and "all" – so-called categorical statements – lend themselves to being represented on paper as circles that may or may not overlap.

Venn diagrams are especially helpful when dealing with logical arguments called syllogisms. Syllogisms are a special type of three-step argument with two premises and a conclusion, which involve quantifying terms. In this unit, you will learn the basic principles of Venn diagrams, how to use them to represent statements, and how to use them to evaluate arguments.

Completing this unit should take you approximately 6 hours.

Unit 5: Fallacies

Now that you have studied the necessary structure of a good argument and can represent its structure visually, you might think it would be simple to pick out bad arguments. However, identifying bad arguments can be very tricky in practice. Very often, what at first appears to be ironclad reasoning turns out to contain one or more subtle errors.

Fortunately, there are many easily identifiable fallacies (mistakes of reasoning) that you can learn to recognize by their structure or content. In this unit, you will learn about the nature of fallacies, look at a couple of different ways of classifying them, and spend some time dealing with the most common fallacies in detail.

Completing this unit should take you approximately 3 hours.

Unit 6: Scientific Reasoning

Unlike the syllogistic arguments you explored in the last unit, which are a form of deductive argument, scientific reasoning is empirical. This means that it depends on observation and evidence, not logical principles. Although some principles of deductive reasoning do apply in science, such as the principle of contradiction, scientific arguments are often inductive. For this reason, science often deals with confirmation and disconfirmation.

Nonetheless, there are general guidelines about what constitutes good scientific reasoning, and scientists are trained to be critical of their inferences and those of others in the scientific community. In this unit, you will investigate some standard methods of scientific reasoning, some principles of confirmation and disconfirmation, and some techniques for identifying and reasoning about causation.

Completing this unit should take you approximately 4 hours.

Unit 7: Strategic Reasoning and Creativity

While most of this course has focused on the types of reasoning necessary to critique and evaluate existing knowledge or to extend our knowledge following correct procedures and rules, an enormous branch of our reasoning practice runs in the opposite direction. Strategic reasoning, problem-solving, and creative thinking all rely on an ineffable component of novelty supplied by the thinker.

Despite their seemingly mystical nature, problem-solving and creative thinking are best approached by following tried and tested procedures that prompt our cognitive faculties to produce new ideas and solutions by extending our existing knowledge. In this unit, you will investigate problem-solving techniques, representing complex problems visually, making decisions in risky and uncertain scenarios, and creative thinking in general.

Completing this unit should take you approximately 2 hours.

Study Guide

This study guide will help you get ready for the final exam. It discusses the key topics in each unit, walks through the learning outcomes, and lists important vocabulary terms. It is not meant to replace the course materials!

Course Feedback Survey

Please take a few minutes to give us feedback about this course. We appreciate your feedback, whether you completed the whole course or even just a few resources. Your feedback will help us make our courses better, and we use your feedback each time we make updates to our courses.

If you come across any urgent problems, email [email protected].

Certificate Final Exam

Take this exam if you want to earn a free Course Completion Certificate.

To receive a free Course Completion Certificate, you will need to earn a grade of 70% or higher on this final exam. Your grade for the exam will be calculated as soon as you complete it. If you do not pass the exam on your first try, you can take it again as many times as you want, with a 7-day waiting period between each attempt.

Once you pass this final exam, you will be awarded a free Course Completion Certificate .

Saylor Direct Credit

Take this exam if you want to earn college credit for this course . This course is eligible for college credit through Saylor Academy's Saylor Direct Credit Program .

The Saylor Direct Credit Final Exam requires a proctoring fee of $5 . To pass this course and earn a Credly Badge and official transcript , you will need to earn a grade of 70% or higher on the Saylor Direct Credit Final Exam. Your grade for this exam will be calculated as soon as you complete it. If you do not pass the exam on your first try, you can take it again a maximum of 3 times , with a 14-day waiting period between each attempt.

We are partnering with SmarterProctoring to help make the proctoring fee more affordable. We will be recording you, your screen, and the audio in your room during the exam. This is an automated proctoring service, but no decisions are automated; recordings are only viewed by our staff with the purpose of making sure it is you taking the exam and verifying any questions about exam integrity. We understand that there are challenges with learning at home - we won't invalidate your exam just because your child ran into the room!

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Saylor Direct Credit Exam

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Logical Thinking vs Critical Thinking: Comparing and Breaking Down the Differences

Many people use the terms logical thinking and critical thinking interchangeably; however, there are subtle differences between the two. 

On the one hand, logical thinking is pretty straightforward. 

It’s a method of thinking that uses logic or analysis of information to evaluate a situation. 

Critical thinking, on the other hand, is a process that utilizes logical thinking but takes it a step further. 

To think critically is to question the face value, connect the dots, and seek the truth. 

Get a Question-Based Critical Thinking Exercise—Free!

Introduce critical thinking gently & easily with thought-provoking exercises.

What Is Logical Thinking?

Logical thinking involves thinking in a disciplined manner. Everyday we come across situations where we need to determine what is going on and why. 

The process may be as simple as evaluating product information or as complex as embracing (or not) an opportunity that requires a significant life change. 

You probably don’t toss a coin in the air to make important life decisions. Instead, you analyze the facts and use reason to help you make good choices.

Let’s look at the example of a job opportunity in another state. 

It might sound like a fantastic career move, but applying a big of logical thinking before you take the leap can mean the difference between a positive outcome and one you’ll regret. 

• What will it cost you to move? 
• Is the cost of living higher in the new city than where you currently live? 
• What is the crime rate like?
• Is the city governed well?
• What about increased time commitment? Work load? 

Observing and analyzing all the facts and scenarios can help you come to a well reasoned conclusion—and that is logical thinking in a nutshell. 

What Is Critical Thinking?

Critical thinking is closely related to logical thinking. It involves the questioning of data, beliefs, and information to make a reasoned conclusion or decision. 

It’s the ability to take various ideas or pieces of information and make connections between them. 

Using the example above, if you were offered a great job opportunity in another city, you still consider all the same factors previously mentioned.

However, with critical thinking, you move beyond hard facts and ask things like:

• How do your kids feel about changing schools?
• Do the opportunities offered outweigh the disadvantages? 
• Why would the new job be better than what you have now?

Let me put it another way by posing another question:

Do you take whatever you’re presented with and assume that it is just so? Precisely as described and portrayed?

Likewise, that new career may look good on paper, but what about the invisible factors that go beyond the facts and figures in your contract?

Seeking truthful answers to those not-so-black-and-white questions is the definition of critical thinking. 

Logical Reasoning vs Critical Thinking: The Relationship Between the Two

As touched on earlier, logical reasoning involves assessing facts to arrive at a valid conclusion.

With no assumptions being made and emotions removed from the equation, the principles of logic can be used much like you would use a math formula to solve a problem. 

There’s a clear distinction between right and wrong. 

In theory, given the same situation with the exact same information, two different people would arrive at the same conclusion.

On the other hand, critical thinking involves questioning the answers and information you get. 

For instance, you might investigate if the person providing the information has a vested interest in a particular outcome and how that influences the information provided. 

You may also ask yourself if you’re missing information or how reliable your source is. 

There’s definitely a blurred line between logical reasoning and critical thinking, but the connection is this:

Logical thought processes involve critical thinking, and using critical thinking skills involves a bit of logic.

Is Questioning and Reasoning the Same Thing?

Reasoning involves the use of both deductive and inductive processes to reach a conclusion. 

“Deductive” is just a fancy word for following a fact (or idea, statement, and so on) to its logical conclusion. 

“Inductive” reasoning provides room for one’s own experiences and observations along the pathway to a conclusion. 

In short, to reason is to use logical thinking to evaluate and determine then explain your approach to a problem.

Questioning, on the other hand, is different than—though part of—reaching a reasoned conclusion. 

Questions help you dig up more information so you can reason effectively to determine the truth of a matter. 

So essentially, questioning is just one part of reasoning. They are not one in the same. 

How to Strengthen Your Critical Thinking Skills

When a situation calls for forming your own opinion or making a decision, it’s important to know how to think as opposed to being told what to think.  

I t’s all too easy to be swayed by popular opinion. 

That being the case, it’s important to pause amid the clamor and think both logically and critically to ensure you know exactly what you believe instead of simply following the crowd. 

Doing so also equips you to make choices based on your personal values, beliefs, and goals.

You can strengthen your critical thinking skills by thinking through situations, one step at a time. 

You’ll gain knowledge as you gain real-world experience, but that database of knowledge isn’t going to serve up a solution for every problem you face. 

That’s where the ability to think critically becomes so important. 

Practice asking questions while questioning assumptions. 

(Here’s a list of fun critical thinking questions that are more lighthearted if you need help getting started.)

Pay attention to the processes you use to analyze information and reach conclusions.

Take time to break down any barriers to critical thinking that may exist.

Today, we are spoon-fed so much information on social media and the internet that thinking sometimes seems irrelevant, but oh what a dangerous path that is. 

If you don’t already, begin questioning the things you read and hear. 

Do your own research. 

Question commonly accepted facts. 

Analyze the information you receive and from whose mouth you receive it from.

Of course, not every little situation requires an in-depth analysis or use of critical thinking skills. 

Family and friends won’t appreciate being questioned about everything they say or do. 

Still, judicial use of logical thinking and critical thinking skills can help you become more informed about what is true and what is not.

If you want to help your teen sharpen those skills, check out our award-winning curriculum, Philosophy Adventure .

will your children recognize truth?

About the author.

Jordan Mitchell

Parents' Guide

Developing critical thinking in teens, introduction.

For children aged 13 and older, the development of critical thinking continues to build from the skills acquired and the challenges faced in the first two developmental stages. These skills must continue to be reinforced as the child matures.  

The four basic aspects of critical thinking we examined in the first part of this guide, concerning children aged five to nine , remain relevant, therefore. 

Critical thinking based on arguing a point.

Developing self-esteem, the foundation of critical thinking.

Emotional management, a prerequisite for critical thinking.

The social norm of critical thinking.

We also saw new elements come into play between ages 10 and 12 in the acquisition of critical thinking and reasoning skills. These are likewise still important in considering the development of critical thinking in young teenagers:

The development of reasoning skills beyond argument.

Puberty and its implications in terms of interests, self-esteem, and emotional management.

The digital world, via gaming, the internet, and a burgeoning social or pseudo-social life (on social media targeted at young people).

To these concerns are added new set of factors come into play in later adolescence as the cognitive system matures and social life changes. These factors will hugely increase the critical potential of 13 to 15 year olds, while at the same time limiting it in certain respects. These factors are:

The development of formal logic, allowing for more and more complex and abstract lines of reasoning.

New social pressures, including heightened peer pressure and anxieties over social integration. The influences of groups and gangs, which tend to critique the established social order, can also lead to a conformity in attitudes and ways of thinking within the group.

Critical analysis of sources of information and the strengthening of interpretive skills.

Critical thinking in group projects, and as an element of citizenship and social progress .

Beginning at age 13, adolescents can begin to acquire and apply formal logical rules and processes. The rudimentary logic learned at previous stages can now be refined by teaching adolescents some more advanced logical notation and vocabulary, which are outlined in the coming sections. It is important to keep in mind, again, that critical thinking extends far beyond logic, offering tools to apply more broadly to arguments and information encountered in the everyday world.

In the teenage years, social pressures accelerate, and with the internet and social media, these pressures move faster and with more force than ever. As outlined in section two below, critical thinking can prove a valuable resource for teenagers to help cope with these pressures and resist the groupthink that easily emerges in social cliques both online and offline. Critical thinking can also play a role in helping young adults choose and pursue emerging goals, by constructing long-term plans and methods. Finally, critical thinking is an indispensable tool in helping young people understand and analyze the wealth of information sources now bombarding them.

1. Formal Logic

From ages 11 to 12, there gradually develops what Piaget called the formal operational stage . New capabilities at this stage, like deductive (if-then) reasoning and establishing abstract relationships, are generally mastered around ages 15 to 16.

As we saw, by the end of this stage, teenagers, like adults, can use both formal and abstract logic—but only if they have learned the language of logic (“if,” “then,” “therefore,” etc.) and have repeatedly put it to use. Under these circumstances, children learn to extrapolate and make generalizations based on real-life situations. 

At the age of 13 and older, children can begin to learn the rules of formal logic and further hone their critical thinking skills. Whether or not their children are learning these skills in school, parents can help by discussing how to analyze concepts and arguments.

Thus, from ages 10 to 12, by stimulating children intellectually—urging them to reflect and establish lines of reasoning—they gradually become able to move beyond a situational logic based on action and observation onto a logic based on rules of deduction independent of the situation at hand.

This ability to manipulate abstract symbols consolidates by around age 15, provided that one has been versed in formal logic.

A and B are two logical propositions, such that A is the opposite of B. From this, we may formally deduce (without reference to  anything concrete) that the proposition P, which states “A or B,” is always true. There are no alternatives, so P fulfills all possibilities. We may also deduce that the proposition P 1 , “A and B,” is always false.  Here, two contradictory propositions cannot both be true. If one is true, the other is false.

These formal operations require both a mature central nervous system and a mature cognitive system. But, since such examples of formal reasoning are detached from everyday life, they require deliberate practice. Even an adult who is out of practice can struggle with formal reasoning.

After working through several examples, parents can help children extract the logical rules behind those examples.

We can present these two rules of logic using more concrete examples, which makes formal reasoning at once more accessible and less intimidating. In concrete form, however, the reasoning will be less easily applied to new situations. 

Moving away from situational lines of reasoning allows teens to extrapolate and apply logic to the ever more complex challenges and life events they might encounter as they mature into their young adult years. Without formal logic, young teens and young adults won’t be able to define their formal reasoning abilities to extend past situational deductions and personal life experiences or form larger connections with their surroundings and the human experiences that occur around them everyday.

Once they learn to abstract from concrete examples and express these rules in formal logic, children can form and manipulate logical notation and apply it to a multitude of situations. 

If proposition A is: “this salmon is farmed,” proposition B (the opposite of A) will be: “this salmon is not farmed.” B could also be expressed  as: “this salmon is wild.” It is easy in this concrete context to see that P, “A or B,” is always true. A salmon must either be farmed or wild. It is also easy to conceive that P 1 , “A and B,” is always false because a salmon cannot be both farmed and wild.

How can we help children from age 13 and older improve their formal logical deduction skills?

We must start by working on these two rules through concrete examples like that of the salmon. After working through several examples, parents can help children extract the logical rules behind those examples. This is the inductive phase: from concrete examples, we extract the common features and express them in a formal rule. 

Next, it will be necessary to prove this rule solely by logical deduction. If we do not do this, we cannot be certain that the rule is valid in every context. Extracting the common features only results in rules which, at this stage, remain merely hypothetical. Only reasoning allows for the generalization of a rule.

Once students have mastered a collection of formal rules, they can be trained to recognize, within a problem or a given context, what rule is applicable. That is, they can take an initial claim (a hypothesis), apply a rule of deduction to it, and arrive at a conclusion.

2. Faulty Reasoning

Despite the fact that young children may not be able to grasp logical concepts, they still employ everyday forms of reasoning in both their use of language and in problem-solving and decision-making. It is from out of these capacities that critical thinking can begin to develop at this age.

As is readily apparent, communication via language is not logical. Natural language does not conform to a formal logical structure. It is contextual, whether we are talking about comprehension or expression. If someone says: “If I had a knife, I would cut my steak,” most people would understand that having a knife makes it possible to cut the steak. However, in formal logic, the sentence means that if I had a knife, I would be obliged to cut the steak. Logical language is systematic and obligatory. But a child learns to speak and to understand in a pragmatic and contextual, not logical, fashion.

One important way teenagers can improve their logic and reasoning skills is by using formal definitions. These are necessary for more precise and universal reasoning and can help children identify faulty reasoning.

Integrating these topic into family discussions can be enormously productive.

Extension vs. Intension

One idea in formal logic that can be valuable to learn at this age has to do with how concepts are defined. For very young children, categories or concepts are defined according to how they are encountered in everyday life. For example, the general concept of color is determined by all the examples of colors children have come across or imagined. The concept covers all these different experiences. This is called the concept’s “ extension .”

But it is important that children from the age of around 13 start to learn to define concepts not merely according to their extension, but in a formal, scientific manner.

For example, instead of using a definition drawn from experience, students can explain that a color is a perception that our eye, linked to the brain, produces when an electromagnetic wave of a given frequency hits our retina. This definition according to the formal, internal qualities of the concept is called the concept’s “intension.” 

Definition by intension is more complicated, but it allows for the use of the concept in formal reasoning. Therefore, definition by intension gears the child’s mind towards higher-level abstract reasoning. 

For example, if we have to determine whether or not a given entity is a color or not, the intensional definition will offer us formal criteria for making a judgment.

Here’s another example. The prime numbers can be defined formally by intension: they are “the numbers that are only divisible by themselves and one.” If we were to learn only the extension of the term “prime number,” on the other hand, we would only have a list of the numbers that we know are prime.

It is clear that if we only have this definition by extension and we encounter a new, very large number — higher than the largest number on the list we’ve learned—we will have no criteria for knowing whether it’s prime. But if we have the formal definition by intension, we will, with the help of a calculator, be able to determine whether it is only divisible by one and itself and, therefore, prime.

We can’t productively critique the arguments of others if we don’t share their definitions of concepts.

When we are young, we learn about the world through definitions by extension during the course of our interactions with objects and other people. Our brain defines concepts by extension and then extracts the common features to produce a working definition. 

But these definitions are subjective since they depend on our history of encounters with relevant examples. Thus, all of the concepts we have created do not match other people’s concepts precisely, despite being identically named. They depend on the particular experiences we have had.

Yet, towards the ages of 13 to 15, with mathematical and formal logic, it becomes possible to define concepts by intension and, therefore, to share objective meaning with others. Teenagers can enter a world  of shared and precise meanings. This is a prerequisite for the application of precise and formal critical thinking. We can’t productively critique the arguments of others if we don’t share their definitions of concepts.

The formal approach for children aged 13 and up should, then be twofold: formalize the definition of the concepts used and formalize the logical deduction itself. This comes with practice and enhances both children’s capacity to communicate and their critical faculties.

The Concepts of Intension and Extension​

Recognizing faulty reasoning.

As has been discussed in previous sections, developing critical reasoning requires more than simply knowing how to reason formally and contextually. It is also necessary to learn how to recognize flaws in the reasoning of other people who may wish to convince us of their way of thinking, either for narcissistic reasons or to lead us to act to their own advantage.

Such flaws can occur on several levels:

Erroneous rules of logic, leading to false reasoning based on reliable hypotheses.

False hypotheses (starting points for reasoning): even if the reasoning is valid, the conclusion may be false. Certain politicians use this strategy very frequently.

Using a formal rule in a situation to which it does not apply. This often occurs in over-simplified mathematical modeling of complex material, for example when an essay in the humanities is interpreted using only the tools of formal logic. 

These three types of flaws can be worked into family discussions, with the goal of training children to counter weak or manipulative lines of argument. School should not be too heavily relied upon to provide this kind of practice for your children. Already between the ages of 13 and 15, they are able to construct brilliant lines of reasoning, which will prevent them from being tricked by manipulative or intellectually limited people.

Flawed Reasoning​

3. individuation, what is individuation.

Individuating and the stages of individuation are concepts developed by renowned analytical psychologist Carl Jung . Jung founded analytic psychology and the concepts of extraverted and introverted personalities, archetypes, and the collective unconscious were also developed by Jung along with the theory of individuation.

In adolescence,  the individuation process heralds the initial stages that a child takes toward  becoming a unique individual, something more than just your parents’ offspring, is a psychological necessity. 

Part of differentiating yourself from the world around you is developing a self-image. It is the only way to avoid fading completely into your surroundings—and ending up in utter conformity, or worse.

Teenagers have a natural impulse to try to separate themselves from their parents and their backgrounds. A good critical thinking foundation can help ease the transition toward individuality and adulthood. Better reasoning can help teenagers cope with their emerging independence and avoid an unthinking rejection of their background.

Individuation adolescence

Individuation is indispensable to society. In order to sustain itself, society needs diversity. Cultures lacking the social norm of individuation are more fragile. They produce citizens who have identical self-images and behavioral patterns, whereas adapting to change requires diversity, creativity, evolution, and, therefore, critical thinking.

Only very rarely (or not at all) have individuals in these cultures of weak individuation experienced the feelings of crisis and malaise we associate with adolescence. The transition from childhood to adulthood unfolds instead according to so-called “rites of passage.” 

Our civilization has undergone a long and profound evolution through philosophy, science, psychoanalysis, and politics, leading us to a social norm that rejects the idea that the individual in the family, the social group, or the nation, is like a mere cell in an organ. Indeed, everyone has the right and even the “duty” to be reborn by deviating from their origins. 

This is an immense challenge because this act of individuation, this self-creation, arises at a moment when children are not yet able to achieve this “rebirth” autonomously, as they enter an unknown world without even knowing what it will be like. We call this period “adolescence” or even “kidulthood” when it lasts a long time—a growing phenomenon.

Experiencing society predominantly through school or family simultaneously generates pressure to conform and to individualize. It comes as no surprise that this causes some problems.

The desire to be free and independent generates psychological conflict.

What is the process of individuation.

Children have not fully matured intellectually or cognitively when they are confronted with this contradiction. They are, therefore, unable to conceptualize it. This is why, in their behavior and attitudes, children can sometimes bear a closer resemblance to skittish animals than calm self-creators responsible for their own gradual reinvention.

Although unaware of it, children embark upon adolescence through “second-degree” conformity through culture, since adolescence is a societal construct rather than a psycho-behavioral component of puberty. 

Paradoxically, children aged 13 to 15 or older may not experience teenage angst at all, thanks to their critical faculties. In fact, if they feel that their life is fulfilling and stable, they will be able to avoid getting sucked into an alternative world by other children their age. Their youth may pass without them having experienced teen crisis. Instead, they construct their identity reflectively and without drama.  

This, of course, is not typical. The desire to be free and independent generates psychological conflict. The fear and the anxiety associated with this moment of struggle incites rationalizations, thoughts which retrospectively come to explain dissatisfaction, malaise, and rebellion. Every situation that is not comfortable or does not come off successfully, we tend to attribute to our external environment and other people. Consequently, if things are not going well for us—if we are not happy—we tend to blame it on an unjust world.

Parents of teenagers are very familiar with the result: sweeping criticism of everything teens encounter. To the teenager, everyone sucks: parents, teachers, politicians, journalists, and so on. This reaction can generate conflict, but, as is explained in the next section, it also presents a good opportunity for deepening critical faculties.

4. Teenage Negativity

It can be difficult to know how to react to teenagers’ negativity. On the one hand, their attitudes may seem too extreme and unsophisticated to take seriously. On the other, they can be exasperating and even hurtful when directed against the parents themselves. But parents should do their best to avoid being either dismissive or defensive. 

The teenager’s emotional negativity is an extreme version of something we are all prone to indulge in from time to time, no matter how highly we may prize our calmness and understanding. Parents should remind themselves that this negativity is part of a bid to become a fully-fledged autonomous individual with an opinion deserving of recognition and respect. 

Parents can help them reach this goal by taking their teens’ complaints seriously. This doesn’t mean telling them they’re right when they aren’t, but treating them as conversation partners worthy of engagement. Parents can ask their children to substantiate and defend their claims using argument and evidence; challenge their children when they fail to argue well; and compliment them when make good points.

The need to become an individual can often manifest itself in negative and unyielding attitudes. Though teenagers’ criticisms and complaints can be unsophisticated, parents should still engage with them. Critical reasoning can help make the process of becoming an individual less painful and more productive.

This can be a good opportunity for parents themselves to refresh their ability to put aside emotions and handle a topic fairly and dispassionately. By modeling these kinds of intellectual virtues parents make it more likely that their children will adopt them.

Arguing with teenagers can be fun, especially if they begin to experience the kind of satisfaction that comes out of reasoned debate over complicated issues..

Of course these arguments will not always go smoothly, but over time parents can help bring their children into the critical community. Arguing with teenagers can be fun, especially if they begin to experience the kind of satisfaction that comes out of reasoned debate over complicated issues.

  The quest for individuality also manifests itself in a need to create or to win over a new group, a group that can become one’s ideal family. The phenomenon of teenage cliques or gangs—and even radical organizations—arises from this fact. Not being understood or accepted is stifling. We need an escape valve, and so, as social animals, we create or join a group that meets our needs.

Individuation and Belonging

5. sense of belonging in a community, what it means to belong.

Belonging means acceptance into a larger whole, society, community, or organization. It’s a fairly common experience that occurs at many levels of life from the familial unit, to work, to school, to the society as a whole.

From the age of 12 to 13, in order for children to be able to articulate their disagreements with the status quo, they must develop their critical reasoning skills. As adults, we must, again, engage with these critiques if they are well-founded. This shows children that rejecting their endeavors is not the automatic response. This makes them feel valued and capable of exercising autonomous thought which can, moreover, influence adults.

In this way, critical thinking also — perhaps unexpectedly — makes it easier for children to accept at least a part of the cultural heritage that is offered to or imposed on them by language, upbringing, and custom. 

Although they may relentlessly criticize society, in so doing teenagers are really showing that they belong to it. Parents should help teenagers learn to articulate their dissatisfaction and develop a sense of belonging. . Critical thinking can help them reconcile their desire for independence with the value of tradition and belonging to society.

Allowing a teenager to convince others through argument and logical inference makes them feel more able to become an individual without breaking away from the group—a rebellion-free evolution. If they are allowed to articulate their dissent, they may even find school or home life less stifling than social life in a peer group where they are constantly pressured to conform. Encouraging this kind of critical thinking also protects them from negative influences (cults, crime, etc.), since their critical toolkit allows them to stay lucid when faced with wild, dangerous speech and behavior (alcohol, drugs, etc.).

From as early an age as possible, learning how to argue and reason critically using one’s capacities for inference allows for a balance in adolescence between individualization and an acceptance of heritage. 

Indeed, the need to distinguish oneself and to proclaim one’s individuality is always met by membership in a group—now often with the help of social media. This need is only met if these groups are not as prescriptive and stifling as the society from which the child is trying to escape and if they do not cause harm. 

Part of critical reasoning is the development of the capacity to question environmental, familial, and social norms and prescriptions. But this requires competence in a universal language made up of inferential logic and the art of arguing,  which comes from the critiqued society. Critical reasoning itself thus serves as lasting proof that one remains a part of that society.  In the very act of distinguishing themselves from the pack, teenagers show they belong.

Critical reasoning anchors children in reality, allowing them to achieve individuality in their own unique way. Parents can help by supporting their children’s projects and encouraging them to engage with the world around them.

Building a sense of belonging.

Cultural heritage—including language, law, food, art, manners and customs, traditions, and scientific knowledge—represents an incredible resource that is at once imposed and offered. Teaching children critical thinking and reasoning means that they will not simply dismiss this priceless treasure in its entirety even though they will partially free themselves from it. Critical reasoning makes the process of individualization less violent and painful for both children and parents, thanks to the balance between the assimilation of culture and a healthy questioning of it.

In other words, critical reasoning—expressed through argumentative and logical know-how and rooted in self-esteem and love—anchors children in reality, allowing them to achieve individuality in their own unique way. Parents can help by supporting their children’s projects and encouraging them to engage with the world around them.

Cognitive faculties participate, in this way, in the psychological make-up of children. Critical reasoning has a twofold power: it is both integrator and liberator. It alerts us to the ways our culture forms us and helps us partly to overcome it. It is a fundamental pillar of our citizenship, on a national and global scale. 

Benefits of sense of belonging

Critical reasoning serves as proof to children that they are listened to and that they are the primary drivers of their own destinies. Subsequently, they are predisposed to put their faith in the future and in others. They become psychologically and intellectually equipped to imagine a future with other people, in which they undertake communal projects and attain important goals.

6. Analyzing Sources

By the age of 13, young people likely already have significant experience navigating the internet. They have all made extensive use of a variety of websites in order to find answers to their questions or to help with papers and schoolwork.

The internet has democratized the transmission of information, allowing anyone and everyone to put forward their ideas, opinions, or hypotheses on multiple online platforms. People usually post things online in an affirmative style which presents any given statement, no matter how dubious or speculative, as a well-known fact.  

People’s personal blogs, companies’ promotional lifestyle websites, and free encyclopedias all feature articles on complex subjects, almost always with content that has not been vetted by any experts,  whose critical thinking skills and reasoning would be invaluable.

Teenagers need support  to cope with and analyze disinformation and deception online. They should work on developing critical reading and browsing habits and learn to identify different kinds of deceptive reasoning. Families can practice analyzing false or misleading information together. 

Debunking these types of conspiracy theories, with the help of parents and educators, can be a useful exercise for students.

In analyzing these and similar sources, we will arrive at one of five possible situations:

An author has good intentions but his or her reasoning is flawed. The author draws unsubstantiated conclusions from trustworthy information. For example, we have proof that certain particles came out of thin air and did not evolve from anything. Some wrongly conclude that this proves the existence of God, since only God could create something from nothing. This information is true, but the reasoning is false, and the conclusion therefore does not follow. The solution involves the relationship between energy and mass in the equation E = mc 2 . In empty space, even the smallest amount of heat can cause spontaneous conversions of pure energy into matter.

An author has good intentions and reasons well, but uses false information. Here, the author can come to false conclusions, even if he or she reasons impeccably. For example, one could conclude that the acceleration of an object, induced by gravitational force, is dependent on its mass because if one drops a rock and a feather from a balcony, the rock will hit the ground before the feather. Here, the problem lies with the initial information, which is erroneous because it does not take the role of air resistance into account. The observation on which the argument is based is thus incorrect in this case, as is the conclusion. In reality, in a vacuum, the feather and the rock would reach the ground at exactly the same time.

It could be that the hypotheses and baseline observations, as well as the arguments drawn from it, are all incorrect. A false conclusion is likely to result.

Authors could be giving out false information intentionally with the aim of selling a product; harming another individual, group, or country; spreading a rumor to make themselves feel important; or sadistically causing mental anguish to others for their own enjoyment.

An author intends to get a point across by using an argument which appears to comply with logical reasoning but which actually contains one or more inferential leaps , deliberately introduced in order to prove that the conclusion is objective because it stems from rigorous thinking. Sophistry and paralogisms arise from this sort of trickery.

It is very important to expose adolescents to these five possible kinds of lies or deception, as well as to reflect on how to identify them by analyzing authors’ arguments and questioning the hypotheses or observations at the root of their arguments and their likely intentions, given the message’s context. For example, in an advertising context, we can understand that car manufacturers might benefit from lying about the amount of pollution produced by the vehicle they sell.

Nasreddin’s Sophisms

Paralogisms, 7. the critical mind.

General knowledge is also a powerful tool for staying critical and skeptical in the face of this influx of information. It allows one to reconcile information and to check whether new data seems consistent with what they already know.

For example, if one were trying to evaluate arguments about how to address the recession caused by the 2008 global financial crisis, it would be useful to know the history of efforts to boost economic growth through government spending,  especially those undertaken during the Great Depression of the 1930s . Citizens versed in this history will be far better equipped to evaluate and criticize the proposals put forward by politicians and economists in their own time.

Genuine critical thinking requires background knowledge. Parents should help their children acquire broad and deep knowledge so they have the confidence and ability to call sources into question and avoid an unreflective acceptance of authority.

Having general knowledge also means that one does not hold even the most reliable sources sacred, knowing that careful thought often undermines received wisdom.

For example, Einstein’s theory of general relativity called Newton’s law of universal gravitation into question, even though Newton’s law had apparently been confirmed by a wealth of experiments and observations. Einstein’s general knowledge and his independent way of thinking allowed him to postulate that gravity was not simply a force but a warping of space-time in the vicinity of stars. Since then, independent observational astronomical predictions have always supported the theory of general relativity.

Treating certain sources as sacred can be as dangerous as uncritically accepting everything that comes from the internet or elsewhere. The same phenomenon is involved when religious texts are interpreted as legitimizing violence or intolerance.

The interpretation—as well as the cultural, social, geographical, and historical contextualization—of a piece of information is indispensable to the formation of a critical mind. But critical thinking is difficult. It takes training, as well as background knowledge, to determine the reliability of a source, and this determination can never be definitive or certain.

These examples show that if we are responsible for educating adolescents on the verification of sources, we must be careful not to give permanent, definitive credit to any piece of information or knowledge, even if it comes from a seemingly very reliable source. Critical thinking, provided that it does not lead to permanent doubt or paranoia, is truly a way of life, facilitating progress and freedom.

Fact-Checking

Verifying sources, 8. critical thinking and progress.

A goal (or a project or “dream”) is the meeting of, on the one hand, an idea born out of a need or desire and, on the other, a method—an “algorithm” for bringing the idea into reality. But these two dimensions to every goal are, in fact, two sides of the same coin, two facets of creativity. 

As we have seen, the spark for critical thinking comes from self-esteem and unconditional love. This energy is indispensable to living with both a sense of joy and, at the same time, a continual dissatisfaction with the status quo. Taking joy in life is necessary to prevent this dissatisfaction from degenerating into depression or other pathologies. This joy provides the energy needed to turn dissatisfaction into ideas and dreams of change. 

But in order for an idea to turn into a project capable of changing the world, both a methodology and logical, communicative rigor are required. These allow a large number of people to understand a problem in the same terms and gear themselves toward the same objectives. Without these tools, efforts at problem-solving tend to devolve into emotionalism or factionalism.

Critical thinking can help children not only learn to analyze the world around them, but act to try to change it. Good critical thinking can foster productive interests, deeper engagement with social problems, and the attitudes of good citizenship. In this way critical thinking is vital to social progress.

Methodological rigor is rooted in critical reasoning. 

An education in critical thinking and reasoning is the best way to ensure a child can access goal-oriented thinking. A goal, much like the kind of formal logic we can exercise from the ages of 13 to 15, transforms the possible into the tangible. 

Goal-oriented thinking leads children in their adolescence to join or set up active groups or associations. Activity in such groups requires skills in both logic and communication, and it tends to support their further development. It pushes those undertaking such projects to strike a balance between asserting themselves and listening to others—between critiquing and taking what others say on board. 

In this sens e, critical thinking and the drive it inspires to undertake projects can be a kind of citizenship training. To rigorously and plainly critique a complex system (whether it be political, scientific, or philosophical, theological) is always to act as a citizen. It is beneficial to all.

In this way critical thinking not only enables students to reach their intellectual potential; it can also help them find purpose and, through purpose, happiness.  And, ultimately, it can help foster progress and social cohesion through cooperative action.

Critical thinking not only enables students to reach their intellectual potential; it can also help them find purpose and, through purpose, happiness.

These links between critical thinking, undertaking projects, and citizenship should further encourage parents and educators to guide children toward this spirit of joyful dissatisfaction, as well as toward logical reasoning and the art of arguing.

If this mindset is acquired, teenagers won’t need pressure from above to take action as citizens or to participate in projects for social change that are bigger than themselves. There always lies the risk that when parents mandate this kind of participation as a kind of chore, children will reject it out of principle.

Instead of hoping their children will swallow whole what is offered them, parents should encourage them to seek the truth —to learn to reason and argue. Those around them, and society as a whole, will benefit from their skills, their independence, and their spirit.

Reboot Case Studies

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Case Study 1

The concepts of intension and extension.

B eginning at around 13, students can begin formalizing their reasoning using intensional definitions. These formal definitions, which are internal to concepts themselves, rather than drawn from experience, can open up new avenues for reasoning and lead to new kinds of arguments. 

Consider the following scenario:

During a presidential election campaign, 14-year-old Lea defends a candidate who, in her eyes, is the only one worth voting for. She explains her candidate’s platform to her friends around the table at lunch in the school cafeteria and says how she wishes she already had the right to vote and that she begged her parents to vote on her behalf.

Lea’s arguments seem to have convinced her friends, but Anna, sitting at one end of the table, interjects: ″Who cares? As my parents say, all presidents are liars! I’m never going to vote.”

The other girls and boys present agree loudly. A surprised Lea tries to think of a comeback, but can’t think of what to say.

The bell rings. Everyone gets up to go back to class.

When she gets home after school, Lea tells her mother about the scene at lunch and asks her opinion: ″What would you have said to Anna?”

If you were Lea’s mother, how would you have replied? How can you use reason to respond to Anna’s argument, which seems to be an argument from authority ?

There are two ways to determine whether all presidents are liars or not:

• Extensional method: Research the history of presidential elections, and compare the promises made by candidates to their actions after being elected. This method will allow you to determine whether all presidents over the course of history have lied. Perhaps they all have lied. But even in this case, Anna’s argument would be valid but only up to the present day , since one cannot predict the future and, therefore, what a new president will do. Perhaps Lea could then defend her favored candidate by arguing that, once elected, he or she will be different.
• Intensional method: Research political science and show that the electoral system and certain institutions pressure candidates to lie in order to get elected and that this is considered the “rules of the game.” If this can be demonstrated, it would be a valid pattern for the past and the future. In this hypothesis, Anna’s argument will be valid for the present and the future (so long as the same institutions remain in effect). Notice, however, that this method gives Lea an opportunity for more subtle reasoning. All presidents may end up making false promises or misleading the public on certain points, but we can distinguish between deliberate, malicious lies and those that arise from the pressures of the office. This would allow her to poke holes in Anna’s rationale for not voting, since certain candidates may still be more honest than others.

Case Study 2

Flawed reasoning.

Use these examples of flawed reasoning to introduce logical vocabulary and help your children identify flawed reasoning  and how to identify flaws in an argument.. More definitions and basic concepts can be found here .

The examples are based on famous example of deductive reasoning attributed to Aristotle. In the exercises, Aristotle’s example is distorted in various ways, either using false information or faulty reasoning. Challenge your children to identify exactly why these arguments fail. 

Here are some definitions of the terms used below: 

Premises are the statements or information on which an argument is based (in these cases, the first two lines). 

The conclusion (the third line in these examples) is the statement drawn from the premises.

When an argument is valid , that means its conclusion follows logically from its premises.

When an argument is sound , that means it is both valid and based on premises that are true, meaning its conclusion is also true.

These examples can help students to break up reasoning into logical steps, make the logical steps of an argument explicit to themselves, and identify where reasoning breaks down. Critical thinking must enable us to detect logical errors and to recognize whether they lead us to false conclusions. Notice, however, that flawed reasoning does not guarantee a false conclusion. 

Aristotle’s Reasoning

“All human beings are mortal. Socrates is a human being. Therefore, Socrates is mortal.”

The premises are true, the reasoning is valid, and the conclusion is, as a result, true.

All human beings are women. Socrates is a human being. Therefore, Socrates is a woman.

One of the premises is false, the reasoning is valid, but the conclusion is false.

Half the human race is female. Socrates is a human being. Therefore, Socrates is female.

The premises are true, but the reasoning is invalid, and the conclusion is false.

Half the human race is male. Socrates is a human being. Therefore, Socrates is male.

The premises are true, the reasoning is invalid, but the conclusion is true.

Case Study 3

Peer pressure emerges in adolescent social groups as children attempt to assert independence from their parents and build their own identity through involvement in peer groups. This can lead to a number of paradoxical problems as children are pulled between an emerging sense of self and a need to belong. Even as their children seek to separate, parents can offer them help and support in working through some of these conflicts. 

Consider this scenario:

Twelve-year-old David has just entered sixth grade at a big middle school in the city. He is a bit lost and finds a group of boys his age to spend time with during class and at recess. They all get to know each other over the next few weeks.

At the end of October, one of the boys suggests that they draw a big skull and crossbones on their backpacks in permanent marker to show that they belong to the group. Within a few days, all of the boys in the group have proudly drawn a skull and crossbones onto the front of their backpacks— everyone, that is, except David. He really likes his backpack. He picked it out himself and his parents bought it for him for the new school year. Furthermore, he has never had an affinity for skeletons, and skulls and crossbones hold no special meaning for him.

When the group reunites in the playground one Friday morning, one of the boys goes over to David and threatens him, saying, “If you don’t draw a skull and crossbones on your backpack, you’re out of the group!” The other children back the mean kid up.

Over the weekend, David is faced with a dilemma. He can either keep his backpack the way he likes it, even if that means being excluded from the group, or draw a skull and crossbones on it to show that he belongs to the group.

On Sunday night, he decides to talk to his parents about the situation. If you were in their place, what advice would you give him?

At dinner, his father offers him some advice:

″David, you shouldn’t see this as a problem with only two solutions. Just tell your friends that you don’t like either option and that you have another idea.”

″That won’t work. They told me that it had to be one way or the other,” replies David.

″Well, you should at least give it a try,” suggests his mother. “Tell them that you really like being part of the group and that you like them as friends, but that you don’t want to ruin your new backpack by drawing on it. Tell them that, in a group, everyone should have their freedom and that you shouldn’t have to do the same thing as everyone else all the time. Ask them to let you stay in their group, which means a lot to you, without having to do something you don’t want to. That’s a third solution.”

In this situation, the group of boys want David to show he’s part of the group by adopting a common code. David is under pressure to comply and must make a decision. The easiest solution for David would be to succumb to peer pressure. He could also stand his ground and refuse, but this would probably cause him pain since he would have to deal with the group’s disapproval and possible exclusion.

The group does not tolerate non-conformity since it threatens its existence. Eventually, however, resisting peer pressure could play in David’s favor, as his show of independence could earn him the respect of the other group members and thereby bolster his self-esteem.

There is no ″right decision.” Everything depends on David’s level of self-esteem, which will determine his capacity to stand firm in the face of the consequences of his choices.

Case Study 4

Nasreddin, a very famous figure in the Arab Muslim world, was the author of often absurd stories. Families enjoy reading his stories together and refuting his biased reasoning, which is designed to sharpen our critical thinking skills and ability to foil sophistry. Identifying the flaws in Nasreddin’s reasoning is a useful logic game and a good way to introduce logical concepts. Challenge your children to show where Nasreddin goes wrong, and come up with equivalent examples from current events or everyday life that involve the same flawed reasoning.

Very early one morning, Nasreddin was up sowing salt all around his house.

“What on earth are you doing with all that salt, Nasreddin?” asked his neighbor.

“I’m putting it around my house to ward off tigers.”

“But there aren’t any tigers here.”

“Well then, that’s proof that the salt worked!”

The Moon and the Sun

One day, Nasreddin was asked:

“Tell us, Nasreddin, which is more important: the sun or the moon?”

“The moon, of course,” he replied immediately.

“Because the moon appears at night, and that’s when we need light most.”

The Power of Age

Nasreddin arrived at a café one day, looking proud and happy.

“Hey, Nasreddin,” his friends called to him. “You look as if you’ve just found treasure.”

“Even better, even better,” he replied. “I am 70 and I have just discovered that I am still as strong as I was when I was 20.”

“And how did you discover that?”

“Simple! You see that huge rock in front of my house? Well, when I was 20, I couldn’t move it.

“Today, I tried again and I still can’t move it, just like when I was 20.”

Case Study 5

Paralogism Exercise #1

Spot the paralogisms in the following statements and explain why the reasoning is flawed. 

″If smoking were bad for your health, it would be banned. Smoking is not banned. Therefore, smoking is not bad for your health.”

″If I am sick, I go see the doctor. I am not going to see the doctor. Therefore, I am not sick.”

″Intensive farming allows us to feed all human beings. Organic farming is not intensive farming. Therefore, organic farming will not allow us to feed all human beings.”

Paralogism Exercise #2

Three false dilemmas are presented below. Why are these apparent dilemmas not real dilemmas?

A close friend who is going to jump into a freezing lake on New Year’s Eve says, “A real friend wouldn’t let me do this alone.”

The night before election day, a candidate for office says, “It’s me or chaos.”

A slogan in an advertisement for Sneakie sports shoes reads, “Cool people wear Sneakies.”

Paralogism Exercise #3

Often biased or flawed reasoning uses false generalizations. How can we contradict the following statements?

Upon hearing that a  politician is being investigated for tax fraud: “See? All politicians are corrupt.”

“Hypnosis works for giving up smoking. My brother managed to quit that way.”

“Social media is the best way to find love. Several of my friends met their partners that way.”

Paralogism Exercise #4

Beware of an “argument from authority,” especially those circulating online.

″Many scientists dispute the global warming phenomenon.” Who are these “scientists”? On which scientific studies have they based their opinions? Do they have personal, political, or economic connections with people or organizations that could benefit from challenging global warming? It is important to ask oneself all of these questions before accepting an argument.

Paralogism Exercise #5

Arguments based on numbers:

″This singer’s video already has 500,000 views online.”  What does this say about the quality of their music?

″X93 – the latest phone, already owned by 2,000,000 people worldwide.”  Does this mean that this device would suit my needs? Is this an indicator of its quality?

Paralogism Exercise #6

Arguments based on fear:

″You say that you’re against the death penalty, but murder will be much more common if we abolish it as a deterrent.”

Case Study 6

Several media companies offer fact-checking services. It is beneficial to consult them with teenagers and to pose questions about the ways in which media can distort the truth.  These services can offer insight into the techniques various organizations and bad actors use to deceive audiences, as well as into the bias that can skew the information put out by various news organizations. Discussing these examples with your children get help raise awareness of the various ploys used to manipulate readers and viewers, and help them hone their analytical and critical skills.

Here are links to some trustworthy fact-checking sites: Politifact    |   Snopes   |    FactCheck.org   |    Poynter Institute

Examining the false stories fact-checked by these organization can be a helpful exercise. Here is an example of a  false story  fact-checked by Snopes:

Understanding examples like these can give students insight into techniques fake news sites use to hook and deceive an audience. Here, for example, the violent image may grab viewers’ attention and cause them to let their critical guard now. Attaching the fake story to a genuine news item (Samsung’s smartphone recall) also makes readers more likely to believe and share the false story, since it appears like a development in an ongoing story.

Student’s can also learn from the fact-checkers’ analysis. Here, they track down the original photos to show how the fake site has repurposed them, and they dig into the website reputation and background.

Researchers Sam Wineburg and Sarah McGrew recommend teaching students to navigate the internet more like fact-checkers. Students, they write, tend to “read vertically , evaluating online articles as if they were printed news stories.” Fact checkers, on the other hand, “read laterally , jumping off the original page, opening up a new tab, Googling the name of the organization or its president.”

Fact-checkers, Wineburg and McGrew write, are also less inclined to trust a website’s own description of its mission. They look for outside evidence from multiple sources to confirm or refute the website’s claims. And they don’t get hooked by enticing language or images, instead reading through a whole page of search results or information before deciding reflectively what links to follow or where else to look.

Finding good information online — and steering clear of bad information—are skills that can be taught and learned. They are increasingly vital at a time where multiple interests are leveraging the internet to attempt to monopolize our attention and shape our beliefs.

Case Study 7

1. Questioning the Source

• What is the source? Is it reliable? 

It is often possible to cast doubt on a source simply by looking at surface features. There are numerous fake news websites with unusual names or URLs (like, for example, worldnewsdailyreport.com) that should tip readers off to their unreliability. In addition, if a website looks poorly designed and managed, contains typos or formatting errors, this is also an important indicator that it is likely unreliable, if not intentionally false. Fake news also may also come under more plausible publication names, like, for example, the “Denver Guardian,” and with more convincing design. A simple internet search can usually bring up information from credible sources alerting the reader to the fraudulent nature of the source. Here is a list of unreliable news sources from Factcheck.org. With your child, practice determining the reliability of different kinds of information.

Who owns the source? Is the content sponsored?

When evaluating a source, it is also possible to do research into details about the source, such as who owns the source or who is funding the content or supporting it via advertising. It is often possible this way to identify potential biases or attempts to influence readers that may not be immediately clear at a first reading. Reliable sources may also sell space in their publications or websites to sponsors, who have obvious interests in what information is presented and the slant with which it is presented. See for example this “ China Daily ” paid post in the New York Times, which is placed on the Times website by Chinese state media. Exploring how and why information like this is presented can be a good learning experience. It is also useful to discuss how sponsored content is marked on this and other websites.

• Who is the author of the content? What are their credentials? What possible biases may they have?

In addition to asking questions about publications, it is important to know who has written a given article or op-ed , what their reasons for doing so may be, and what expertise they have in the given area. Doing so can help determine the reliability of the information offered, the possible slants or biases with which the information is presented, and any financial or other interest the writer may have in the matter discussed. Most reliable websites will offer at least some of an opinion writer’s background, but an internet search can often return more detailed information. It is also important to help students recognize that an editorial author’s potential biases do not necessarily render the content absolutely unreliable. Critical thinking should not lead to knee-jerk rejection of all potentially biased opinions. Rather, a fair-minded independent thinker takes potential bias into account in evaluating content, weighing it along with other factors, like the strength of the argument and the evidence put forward.

2. Questioning the Content

• What type of content is being offered? What is the issue under discussion?

Before we embark on an analysis of the content of a given source, it is important to identify what type of content is being offered. The way we approach analyzing an advertisement will be very different from the way we analyze a news story or an opinion piece. It’s also important that students be able to identify when a particular source is purposefully blurring the lines between categories. For example, so-called “advertorials” can disguise advertising or promotion in the guise of opinion pieces or feature articles. News stories may likewise present information in a particular misleading or biased manner, trying to persuade the reader of something, but without making it clear that they are actually offering an opinion, not simply news.

• What sources are drawn on for the information or argument given? Are they reliable?

Even when we are satisfied that a source we are reading is generally reliable, it is worthwhile to pay attention to its own sources of information. If a particular piece of content cites facts without providing sources there is good reason to question the information. Moreover, students should get in the habit of following links and citations to verify that the secondary information comes from a reliable source and that the original content is characterizing it accurately.

• What are the main arguments being offered? Are they strong and sound? Are they consistent with each other?

Media sources use a variety of means to try to convince the audience of a particular point or point of view. It is important to train ourselves to be conscious of what these means are and whether they are valid. If an article or video simply relies on emotional reactions or strong images to prove its point, without trying to put forward an argument, we should be skeptical. On the other hand, if there is an argument presented, we should begin training children to break it down and analyze it. Parents and their children can practice breaking down the argument into premises and conclusions, evaluating whether the evidence for the premises is strong and the conclusions follow rationally from them.

• How might one argue against the position put forward?

Another important exercise to carry out, even if you generally agree with a position put forward, is to ask how it might be opposed. This can help identify weak points in the argument and show where evidence, even if it’s reliable, may not fully support the point of view being put forward. To this end, it can be helpful to research articles with opposing points of view, but which rely on the same set of facts. Discuss the merits of each article and how you would argue for and against each of them. 

Complete the quiz to review important points in the guide.

• The stage when children start dressing more elegantly.
• The stage when children begin arguing more persuasively.
• The stage when children can begin to grasp and manipulate abstract ideas.
• The stage when children are able to study calculus and other college-level math.
• Parents can discuss logical fallacies in popular media or current events with their children.
• Parents can work on improving their own understanding of logic.
• Parents can go over children’s essays and other schoolwork closely and dispute their reasoning.
• Parents can enroll their children in college exam prep courses as early as possible.
• Parents can use everyday examples to demonstrate the meanings of terms like proposition, contradiction, and validity.
• The intension is how the concept is used; the extension is a formal definition of the concept.
• The intension is a narrow definition of the concept; the extension is a broader definition.
• The intension is a formal definition of the concept; the extension is a group of examples coming under the concept.
• The intension is the role a concept plays in logic; the extension is its role in everyday life.
• Critical thinking gives them tools to show their superiority to their peers and gain social esteem.
• As critical thinkers, they will be better equipped to manipulate other people and make their way to the top of social circles.
• Critical thinking allows them to react thoughtfully to social pressure and assert their independence from friend groups when appropriate.
• As crtical thinkers, they will be more likely to concentrate on their studies and ignore social life and their own individuality.
• Walk away. Teenagers need to learn that overheated opinions and conversations will get them nowhere.
• Bring in a teacher or other adult authority figure to mediate. The parent-child relationship is too emotionally charged for productive arguments.
• Get into shouting matches with them. They need to see that their mistakes have consequences.
• Engage them in arguments and challenge them to improve their criticisms (if they’re warranted). They’ll learn to argue with more moderation and subtlety.
• Is the content meant to be news or opinion?
• Does the content’s impact rely on emotional language or sensationalistic images?
• Who owns the source? Or who is supporting the content? What interests might they have?
• Was the author educated at a prestigious college?
• What do other reliable sources say about the issue under discussion?
• The study of planetary orbits
• A convincing counterargument
• The merging of two arguments into one
• A deceptive or misleading argument

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• Informal Logic

The study of logic has often fostered the idea that its methods might be used in attempts to understand and improve thinking, reasoning, and argument as they occur in real life contexts: in public discussion and debate; in education and intellectual exchange; in interpersonal relations; and in law, medicine and other professions.

Informal logic is an attempt to build a logic suited to this purpose. It combines accounts of argument, evidence, proof and justification with an instrumental outlook which emphasizes their usefulness in the analysis of real life arguing. Blair 2015 identifies two key tasks for the informal logician: (i) the attempt to develop ways to identify (and “extract”) arguments from the exchanges in which they occur; and (ii) the attempt to develop methods and guidelines that can be used to assess their strength and cogency.

Though contributions to informal logic include studies of specific kinds or aspects of reasoning, the overriding goal is a general account of argument which can be the basis of systems of informal logic that provide ways to evaluate arguments. Such systems may be applied to arguments as they occur in contexts of reflection, inquiry, social and political debate, the news media, blogs and editorials, the internet, advertising, corporate and institutional communication, social media, and interpersonal exchange.

In the pursuit of its goals, informal logic addresses topics which include, to take only a few examples, the nature and definition of argument, criteria for argument evaluation, argumentation schemes, fallacies, notions of validity, the rhetorical and dialectical aspects of arguing, argument diagramming (“mapping”), cognitive biases, the history of argument analysis, artificial intelligence (AI), and the varying norms and rules that govern argumentative practices in different kinds of contexts.

2. Systems of Informal Logic

3. standardizing arguments, 4. testing arguments, 5. informal logic within a broader context, 6. informal logic and philosophy, other internet resources, related entries.

Puppo 2019 provides a recent collection of articles on the history of informal logic and the issues it addresses. In many ways, informal logic as we know it is a contemporary version of historical attempts to explain, systematize, assess and teach arguing for practical purposes.

In ancient times, the First Sophistic is a movement motivated by the notion that one can teach the art of logos in a way that can be effectively employed in public argument and debate. In the century that follows, Aristotle’s logical and rhetorical works — notably the Prior Analytics and the Rhetoric — provide a systematic account of logic and argument which is applicable to an impressively broad range of real life arguments. Today, they remain important works that inform discussions of informal logic.

In modern times, The Port Royal Logic (Arnauld and Nicole 1662, originally titled Logic or the Art of Thinking ) is an attempt to outline a logic that can guide everyday reasoning. It is a celebrated (and often disdained) introduction to the art of arguing which has been published in more than fifty French editions and five popular English translations. It understands “logic” as “the art of directing reason aright, in obtaining the knowledge of things, for the instruction both of ourselves and others” (25). In keeping with this, it provides a practical account of good and poor argument, discussing fallacies, syllogisms, definitions, and deductive and probable reasoning, emphasizing real rather than concocted examples of argument (see Finocchiaro 1997).

One finds other analogues of contemporary attempts to study and teach informal reasoning in nineteenth century textbooks on logic and rhetoric. Richard Whately is of special note in this regard. He began his career as a professor of political economy at Oxford, was appointed Archbishop of Dublin, and attempted to establish a national non-sectarian system of education, writing texts on reasoning that could promote this cause. In many ways, Whately’s Elements of Logic and Elements of Rhetoric (1826, 1830) are close analogues of early versions of today’s informal logic textbooks.

Another important text, critical of Whately, but in the same broad tradition is Mill’s A System of Logic (1882) (see Godden 2014). It defines logic as the “art and science of reasoning,” stipulating that “to reason is simply to infer any assertion from assertions already admitted.” The end result is a broad account of inference which is, like systems of informal logic, designed to inform real life instances of argument.

The first use of the term “informal logic” occurs in the last chapter of Gilbert Ryle’s book Dilemmas (1954). He introduces it in an attempt to distinguish between formal logic and the more varied, less strict, and less defined ways in which we need to assess many of the arguments that are used in philosophical discussion.

In North America, the rise of informal logic as it is now understood is tied to educational trends rooted in the 1960s — a time of social upheaval and protest (most notably, against the War in Vietnam) which produced calls for an education relevant to the issues of the day. This fueled an interest in the logic of everyday argument and the teaching of introductory logic, which was at the time taught with textbooks like Copi’s popular Introduction to Logic (1953).

In Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life (1971), Kahane more fully embraced instances of real life arguing, discussing a wide range of examples in newspapers, the mass media, advertisements, books, and political campaigns. Other attempts to provide a general introduction to logic — by Carney and Scheer (1964), Munson (1976), and Fogelin (1978) — employed the term “informal logic” to distinguish between formal logic and other methods of argument analysis which lay outside of it.

The idea that informal logic should be developed as a distinct field of inquiry was championed by Johnson and Blair at the University of Windsor. They published a popular textbook, Logical Self-Defense (1977); organized and hosted “The First International Symposium on Informal Logic” and edited the proceedings (Blair and Johnson, 1980); established the Informal Logic Newsletter (1978-1983); and ultimately turned the newsletter into the journal Informal Logic (subtitled “Reasoning and Argumentation in Theory and Practice”). In this and other ways, they established informal logic as a field for study, research and development. Their contributions (and those of colleagues at Windsor and in Ontario and Canada) is reflected in the notion that informal logic is a Canadian (or, more narrowly, Windsor) school of argument (see Puppo 2019).

Much of the discussion that has shaped the evolution of informal logic as a field has taken place in a number of journals that have played a major role in its development. They include Informal Logic , Argumentation , Philosophy and Rhetoric , Argumentation and Advocacy (formerly the Journal of the American Forensic Association ), Teaching Philosophy , and (more recently) Cogency and Argument and Computation .

A key catalyst that promoted the development of informal logic was the “Critical Thinking” Movement within education (well described in Siegel 1988, Ennis 2011, and Blair 2021). The movement pushed (and continues to push) for educational developments which make the critical scrutiny of our beliefs and assumptions a fundamental goal, highlighting the significance of reasoning, inference, argument and critical assessment.

In 1980, a California State University Executive Order promoted the teaching of critical thinking and informal logic by requiring post secondary institutions to include formal instruction in critical thinking in their curriculum. According to the order: “Instruction in critical thinking is to be designed to achieve an understanding of the relationship of language to logic, which should lead to the ability to analyze, criticize, and advocate ideas, to reason inductively and deductively and to reach factual or judgmental conclusions based on sound inferences drawn from unambiguous statements of knowledge or belief” (Dumke 1980, Executive Order 338).

The accounts of argument that informal logic and the Critical Thinking movement provide are tied to pedagogical attempts to teach students and learners how to reason well. One result has been hundreds (perhaps thousands) of introductory textbooks used to teach logic, critical thinking, and argumentation skills to university and college students in Canada, the United States, the United Kingdom, Italy, Poland, Chile, and other countries.

Textbooks in English offer many theoretical and pedagogical innovations. Established texts include Battersby 2016 ( Is That a Fact? A Field Guide for Evaluating Statistical and Scientific Information , 2nd ed.); Bowell and Kemp 2014 ( Critical Thinking: A Concise Guide , 4th ed.); Browne and Keeley 2018 ( Asking the Right Questions , 12th ed.); Govier 2019 ( A Practical Study of Argument , 7th ed.); Groarke, Tindale and Carozza 2021 ( Good Reasoning Matters! , 7th ed.); Hughes, Lavery and Doran 2014 ( Critical Thinking: An Introduction to the Basic Skills , 7th ed.); Seay and Nuccetelli 2012 ( How to Think Logically , 2nd ed.); Weston 2018 ( A Rulebook for Arguments , 5th ed.); and Wilson 2020 ( A Guide to Good Reasoning: Cultivating Intellectual Virtues , 2nd ed.).

In Poland, Ajdukiewicz’s Pragmatic Logic (1974) is an introduction to an independently developed “pragmatic logic” which shares similar goals, teaching and promoting tools of logic as a central element of a general education. Its application aims to ensure that students think clearly and consistently, express their thoughts and ideas systematically and precisely, and justify their claims with proper inferences (see Koszowy 2010).

In part because reasoning and argument are ubiquitous and of interest across many disciplines, informal logic has in many ways been influenced by cognate fields which analyze argumentation in some way. The latter include formal logic, speech communication, rhetoric, linguistics, artificial intelligence, discourse analysis, feminism, semiotics, cognitive psychology, and computational modelling. Considered in this broader context, informal logic is a subfield of a broader multi-disciplinary attempt to develop a comprehensive account of real life arguing which is commonly called “argumentation theory.”

Informal logic and argumentation theory have been highlighted at numerous international conferences hosted by organizations committed to the study of argument. Key conferences include nine Amsterdam conferences (and a tenth conference in Zhenjiang) hosted by the International Society for the Study of Argumentation (ISSA); twelve Windsor conferences hosted by the Ontario Society for the Study of Argumentation (OSSA); six Tokyo Conferences on Argumentation hosted by the Japanese Debate Association; three meetings of the European Conference on Argumentation (ECA); eight meetings of the International Conference on Computational Models of Argument (hosted by COMMA), and many workshops on issues of argumentation, dialogue, and persuasion organized by the Polish group ArgDiaP.

1.1 Formal and Informal Logic

One of the driving forces behind the early development of informal logic was a desire for a logic which contained tools of analysis and assessment above and beyond the standard formal methods of the day: propositional logic, truth tables, syllogisms, the predicate calculus, and so on. Johnson emphasizes a “dissatisfaction with formal logic as the vehicle for teaching skill in argument evaluation and argument formation” and a “desire to provide a complete theory of reasoning that goes beyond formal deductive and inductive logic” (2014, p. 11). Though Ryle never developed a detailed account of what he meant by “informal logic,” his comments point in a similar direction.

Philosophers and logicians teaching general courses on argument have often managed the issues that this raises by mixing formal and informal methods of analysis. Though the artificial examples of argument that characterize early editions of Copi (and some other texts that emphasize formal logic) have been roundly criticized (see Johnson 1996 and Blair 2015), other authors more successfully meld classical formal logic and examples of real argument. Harrison 1969 is an example. So are the texts of Pospesel, which contain many examples of real life reasoning which illustrate the patterns of inference associated with propositional and syllogistic logic (Pospesel and Marans 1978, Rodes and Pospesel 1991, and Pospesel 2002). Little 1980 develops an approach to critical thinking and decision making that integrates propositional and syllogistic reasoning.

Some informal logicians moved in an opposite direction, developing versions of informal logic that were independent of formal logic, appealing to alternative accounts of argument borrowed from or influenced by philosophical reflection, or by other fields that study argument (notably, rhetoric, dialectics, and speech communication). Toulmin’s The Uses of Argument (1958) and Hamblin’s Fallacies (1970) became theoretical touchstones for those looking for an informal logic rooted outside of formal logic.

Even in these latter cases, systems and accounts of informal logic shared some core notions with their formal cousins. Most significantly, formal and informal logic assume (i) a premise, inference, and conclusion conception of argument; (ii) the notion that a good argument has premises which are true (or “acceptable”) and a conclusion which follows from them (making the inference the argument depends on “valid” in some way); and (iii) the idea that many arguments can be assessed by treating them as instances of more generalized forms of argument (“schemes of argument” which include standard deductive patterns of reasoning).

Today, informal logic is “informal” rather than “formal” primarily because it studies arguments as they occur in natural language discourse, and not in formal languages of the sort that characterize formal logic. The latter are notable for their rigorously defined syntax, semantics, and grammar, and precisely defined proof procedures. In contrast, arguments as they occur in real life discourse are notable for their use of everyday language; for the many different norms that apply to them in different contexts; and for the diverse ways of making meaning (using pictures, facial expressions, non-verbal sounds, music, etc.) that they employ.

The emphasis that informal logic and its historical precursors place on natural language argument is in keeping with the social and pedagogical goals that motivate their development. The latter are best served by an easily understood, broadly disseminated, understanding of the difference between strong and weak instances of real life argument. Formal methods (Venn diagrams, probability theory — see Zenker 2013, different kinds of formal logic, etc.) can at times support this goal, especially in analyses of particular kinds of argument, but the overriding aim is natural language discourse guided by the principles of successful reasoning.

1.2 Argumentation Theory

Argumentation theory is a broad interdisciplinary field that studies real life argument. Developments in argumentation theory have been greatly influenced by formal and informal logic; pragma-dialectics (developed by van Eemeren and Grootendorst and their Dutch or “Amsterdam” school of argumentation); the Critical Thinking Movement; American speech communication; rhetoric; pragmatics; and the Polish School of Argument (which has published a relevant manifesto ). In its attempt to understand argument, argumentation theory does not hesitate to make use of these and other related disciplines: cognitive psychology, computational modeling, semiotics, discourse analysis, the history of art, AI, and so on.

Above and beyond their study of general methods of argument analysis, argumentation theorists investigate arguments in a variety of ways: by exploring particular aspects of arguing (e.g., onus, burden of proof, or the norms that govern arguments in specific contexts); by analyzing arguments from historical, social, political or feminist points of view; by studying particular kinds of argument (e.g., those expressed in works of art, or those that arise in specific legal contexts); and by investigating the assumptions, conditions (philosophical, epistemological, social, political, institutional, psychological, educational, etc.) which give rise to disagreement, arguing and argument in the first place. In many ways, such endeavors intersect with informal logic.

Theoretically, argumentation theory incorporates three approaches to argument that have been associated with logic, rhetoric, and dialectics since ancient times. Logic understands an argument as an attempt to justify a conclusion, emphasizing its probative or epistemic merit. Rhetoric treats an argument as an attempt to persuade, emphasizing its persuasive force. Dialectics understands an argument as an element of an exchange between interlocutors with opposing points of view, emphasizing its place in an interaction between arguers who argue back and forth.

Like other forms of logic, informal logic emphasizes the epistemic merit of an argument. That said, its development has been greatly influenced by rhetorical and dialectical considerations, for successful real life arguments must convince their intended audiences (the public, scientists, the Members of Parliament, the readers of a particular magazine, etc.) and (as Johnson 2000 emphasizes) include answers to reasonable objections made by those with opposing points of view. Bermejo Luque 2011 has proposed a relevant theory of argument which aims to accommodate logical, rhetorical and dialectical points of view.

As Hansen (2012) emphasizes, there are many different methods that informal logicians use to analyze instances of argument. An account of informal logic needs to make room for the different approaches this implies, at the same time that it explains how they constitute a shared field of inquiry. I will attempt to provide such an account by emphasizing systems of informal logic.

I understand an informal logic system to be a collection of principles and methods designed for the analysis and assessment of real life arguments. Considered from this point of view, informal logic can be described as a field devoted to the creation, study and application of systems of informal logic (or, more simply, “informal logics”) and the issues that this raises.

The first textbook that described itself as an informal logic textbook was Munson’s The Way of Words: An Informal Logic (1976). As his title emphasizes, his book aims to teach a specific informal logic (a specific informal logic system) which outlines one approach to the analysis and assessment of real life argument. Other approaches and other systems are developed in other textbooks and in scholarly discussion.

Different systems of informal logic vary in a number of ways — often, by incorporating formal, rhetorical, dialectical and other methods of analysis to a greater or lesser extent. Many systems propose unique approaches or mix methods that they borrow from other systems. Groarke 2020 has outlined a “BLAST” approach to the identification and definition of systems of informal logic. It defines a specific informal logic system I , as I = { B , L , A , S , T }, where:

• B = the theoretical background that informs I , L = the language used to express the arguments I analyzes, A = a concept of argument, S = a way to “standardize” arguments, and T = tools and methods for testing the strength of arguments evaluated using I .

As I show below, a particular system of informal logic can be defined by outlining and explaining each of its five BLAST elements. When they have been defined, different systems of informal logic and the elements they contain can be more precisely compared, contrasted, and evaluated. Historical precursors to present day informal logic can be investigated from a similar point of view.

2.1 A Concept of Argument ( A )

In many ways, the third element in the BLAST list — a concept of argument ( A ) — is the root of all informal logics. In ordinary discourse, the word “argue” can mean “to disagree,” usually with the further implication that someone does so aggressively. Informal logics, like other logics, assume a narrower conception of argument (so called “argument-1”), which understands an argument as an attempt to resolve disagreement (or potential disagreement) by providing reasons for accepting the point of view that it advances.

This notion of argument is “evidentiary” in the sense that it understands an argument as an attempt to provide evidence in support of some conclusion. The premises in the argument convey the evidence which provides those who consider the argument reasons for accepting the conclusion. As Hitchcock 2007 puts it, an argument is “a claim-reason complex” consisting of (1) premises, (2) a conclusion, and (3) an inference from the premises to the conclusion (and the implied claim that the conclusion is true, likely true, plausible or should in some other way be accepted).

The following sentence, taken from an article in the Houston Chronicle (Devra Gartenstein 28/01/19) is a simple example of argument in this sense.

EXAMPLE 1: Small businesses are important because they provide opportunities for entrepreneurs and create meaningful jobs with greater job satisfaction than positions with larger, traditional companies.

In this example, the word “because” is an inference indicator. It tells us that the initial statement in the sentence (“Small businesses are important”) is a conclusion backed by a premise (that small businesses “provide opportunities...”) that provides a reason for believing it to be true.

The example below is taken from an opinion piece (in the Western Courier 25/10/08) which criticizes conservative groups opposed to research using human embryos.

EXAMPLE 2: This [opposition to embryonic research] is shortsighted and stubborn. The fact is, fetuses are being aborted whether conservatives like it or not. Post-abortion, the embryos are literally being thrown away when they could be used in lifesaving medical research.... Lives could be saved and vastly improved if only scientists were allowed to use embryos that are otherwise being tossed in the garbage.

We can summarize the elements of this argument as follows.

Premise : Fetuses are being aborted anyway (whether conservatives like it or not). Premise : Lives could be saved and vastly improved if scientists were allowed to use embryos that are otherwise being tossed in the garbage. Conclusion : The conservative opposition to embryonic research is shortsighted and stubborn.

This is another example of a simple argument. In real life arguing, complex arguments may contain tens (or even hundreds) of premises, and are usually made up of layers of inference that proceed from initial premises to intermediate conclusions which function as premises for further conclusions, culminating in a “main” or “principal” conclusion.

All systems of informal logic are attempts to understand and assess arguments in the premise/conclusion sense. In view of this, the core value of A in the BLAST definition is shared by all informal logics, though there are many variations that occur when informal logicians expand this conception by adding other elements to it. This can be done by understanding an argument as a premise-conclusion complex which is directed at an audience , or backed by a warrant , or provided as an answer to an opponent who has an opposing point of view. When they expand the definition of argument in these ways, systems of informal logic make an audience, warrant, and/or dialectical context an essential element of a case of argument.

2.2 Theoretical Background ( B )

Other elements recognized in the BLAST definition are notable for the extent to which they vary from one informal logic to another. The different theoretical backgrounds that inform different systems of informal logic ( B in the BLAST definition) are of special note, for they reflect the extent to which the development of informal logic has been a search for new and novel methods of analysis that can be applied to real life arguing. In a particular case, this search may end in Aristotle, in feminist theories of argument, in rhetoric, in dialogue theory, in speech communication, in formal logic, or in some combination of these and/or other theoretical points of view.

The theoretical background that characterizes systems of informal logic can be used to identify, not only specific systems, but also families of systems which share key theoretical elements. Many informal logicians have, to take one example, turned to fallacy theory in their attempt to find a logic that can account for real life arguing. In some cases, the result has been fallacy oriented textbooks which introduce tens or hundreds of fallacies used to dismiss straw man reasoning, hasty generalizations, slippery slope reasoning, and so on (see, e.g., Bennett 2018).

Systems of informal logic that adopt a fallacy approach can be summarized as instances of I in which I = { B , L , A , S , T }, where: B = Fallacy Theory, and T = a set of fallacies used to judge instances of argument. An even narrower set of (“Hamblin”) systems can be defined as systems in which B = Hamblin. This is a family of systems which is rooted in the account of fallacies proposed in Hamblin 1970.

Systems of informal logic that combine fallacy theory with other methods of testing arguments can be understood as systems which define T in a way that includes a specific a set of fallacies along with other criteria for argument evaluation (e.g., Johnson and Blair’s ARS criteria).

2.3 Language ( NL and NL+ )

One key element of informal logic is its focus on arguments as they occur within natural rather than formal languages.

Initially, informal logic texts defined natural language arguments as verbal arguments: i.e. as arguments expressed and conveyed in words associated with some established natural language. This is an important focus given that arguments of this sort are a staple in the kinds of arguing that informal logic emphasizes — in letters to the editor; parliamentary debate; court proceedings; and in essays and books written in defense of some point of view (that humans could colonize Mars, President Trump was misunderstood, socialism is the best political system, and so on).

When a system of informal logic is designed to analyze and assess verbal arguments of this sort, the language of argument they assume ( L in the BLAST definition) consists of the words and sentences (and the rules governing them) associated with some natural language (“ NL ”). This makes the language of argument a complex and nuanced system of meaning which expands the possibilities of argument beyond the “informative” statements of fact that authors like Copi took to be the only legitimate realm of argument. One notable feature of the expanded realm that informal logic studies is the extent to which metaphor and other figures of speech are used to support conclusions — something that must be accounted for in a comprehensive account of informal reasoning.

As the scope of informal logic has expanded to provide a more comprehensive account of ordinary argument, this verbal paradigm has frequently been expanded to make room for real life arguments which depend on non-verbal elements. Paradigm examples of these non-verbal elements are photographs, illustrations, drawings, videos, etc. which are used to provide evidence in support of some conclusion -- as when a photograph or video is used to prove someone’s identity, or produced in court to give the court a reason to believe that they were present at the scene of a crime. As Hitchcock (2002) notes, “a poster with a giant photograph of a starving emaciated child and the words ‘make poverty history’ can reasonably be construed as an argument.”

Arguments that employ premises and/or conclusions that arguers convey using non-verbal visual elements are commonly called “visual” arguments. I leave for elsewhere the question whether such arguments are visual in some deeper sense. In most cases, they have verbal as well as visual elements and can, in view of this, be described as arguments which are expressed as an amalgam of verbal and non-verbal (visual) elements.

The two photographs in EXAMPLE 3 (below), taken by the NASA Mars rover Phoenix, were part of a visual argument proposed by the NASA scientists who directed the Phoenix mission. The first photo provides an initial view of a dig made by the rover; the second a view of the same dig four Martian days (sols) later. When we look at the bottom left hand corner of the first photograph and compare it to the bottom left hand corner of the second photograph, we can see white crust in the first photograph but not the second. According to the NASA scientists, the only way to plausibly explain this change is by understanding the crust as water ice which evaporated when the dig exposed it to the sun.

We can summarize the argument as follows.

EXAMPLE 3: (Visual) Premise : What we see in the bottom left hand corner of the first photograph of the dig. (Visual) Premise : What we see in the bottom left hand corner of the second photograph of the dig. (Verbal) Premise : The most plausible way to explain the changes we see (the disappearance of the white crust) is by understanding it as water ice. Conclusion : There is water on the planet Mars.

This argument can be described as visual and verbal. Visual because our looking at the photographs and seeing the difference between them is a non-verbal component of the argument that provides key evidence that supports the conclusion. At the same time the argument is verbal because it contains a key verbal component provided by the scientists’ explanation of what we must be seeing. The conclusion is established by combining these visual and verbal components.

When a system of informal logic recognizes visual arguments of this sort, the value of L in its BLAST definition can be understood as NL+ , where the + indicates that the language of argument includes words and non-verbal elements like photographs and other non-verbal visual images.

One might compare the expansion of informal logic to account for visual arguments to the attempt to expand the language of formal logic (and, some argue, the notion of argument it embraces) to allow visual deductions (see Barwise and Etchemendy 1998). Visual premises can be used in geometric proofs, in legal arguments (to proving that someone committed a crime, that the murder was heinous, etc.), in reasoning about planets, stars and black holes, and in aesthetic criticism and evaluation. In ornithology, a well authenticated, clear photograph of a rare species (say, the Ivory Billed Woodpecker) is widely accepted as the proper proof that the species is not extinct.

In other cases, a visual image may serve as a conclusion which is backed by visual and/or verbal premises. A forensic artist concludes that their drawing of a suspect correctly depicts what they look like by inferring this from verbal and visual evidence which is provided by the witnesses they interview.

Kjeldsen 2015 has provided a comprehensive overview of the study of visual arguments. Informal logics that recognize visual arguments do so for the same reason that they recognize verbal arguments: in order to account for the kinds of arguing that play an important role in real life discourse and exchange. Visual arguments are increasingly significant at a time when digital communication facilitates the creation and distribution of visual images, enhancing and increasing the use of arguments which employ photographs, videos, art, political cartoons, virtual reality, 3D modeling and other kinds of visuals (see Godden, Palczewski, and Groarke, 2016).

As is the case with words, the images used in visual arguments may, as Kjeldsen and other rhetoricians point out, not be intended as literal depictions of something they represent, but function as visual metaphors which characterize some situation in an argumentatively charged way.

The cartoon of Napoleon III below (EXAMPLE 4) appeared in Punch on Feb. 19, 1859.

This is a clever caricature, but it is something more than a simple caricature, for the cartoonist uses a drawing of Napoleon-as-porcupine to convey a reason to doubt his profession of peace. We might summarize his point as the suggestion that Napoleon’s actions -- his amassing of the armaments which encircle him like quills on a porcupine -- are not the actions of someone committed to peace. The dissonance between his actions and his profession of peace invites the viewer to respond to him as they would respond to an actual porcupine -- with caution, concern and suspicion, wary of what he might do with his weapons (even though he has an “inoffensive” posture and makes an inoffensive sound).

In this case the visual image in the argument is not an attempt to literally replicate some state of affairs. The core argument we might extract from the cartoon can be understood as follows.

Premise : Napoleon declares that “The Empire embodies peace” (“L’Empire c’est la paix”). Premise : Napoleon has surrounded himself with many armaments. Conclusion : Napoleon may sound inoffensive when he says that “The Empire embodies peace,” but his build up of armaments suggests we should be wary of the empire he has built.

This is a visual argument (and the second premise a visual premise) at least in the sense that it is conveyed visually (and not with the words in our paraphrase). The verbal paraphrase summarizes the argument, though the non-verbal visual elements the cartoonist uses must be replicated if we want to exactly replicate their act of arguing. This is especially important when such arguments are open to contrary interpretations or have meanings that are difficult to convey in words.

In the case of the Punch cartoon, we might interpret it in a second way by adding to our initial paraphrase, understanding the Napoleon III-as-porcupine caricature as an allusion to another famous “Louis” King of France: Louis XII, who ruled from 1498 to 1515. Popularly known as the “porcupine” King of France, he adopted the animal as his royal emblem, portraying the French kingdom as a porcupine -- an animal he chose because it was popularly believed (to some extent now as well as then) that it could shoot its quills, symbolizing the offensive and defensive capabilities of the king’s army.

If we understand the cartoonist’s depiction as an allusion to Louis XII, the argument in the cartoon is plausibly assigned another premise that reminds the viewer of the rule of Louis XII, a king who was famous for rebuilding the French army, which he then employed in a series of wars against his neighbors (his general strategy is criticized by Machiavelli in The Prince ). The additional premise can be summarized as the suggestion that Napoleon is acting like Louis XII did — something which provides another reason to be wary of him.

In many circumstances, the visual elements of an argument (like verbal elements in arguments which are ambiguous or vague) are open to multiple interpretations. This raises issues of representation and interpretation. In the Napoleon example, it is difficult to say whether the cartoonist or his audience understood his depiction to be a reference to Louis XII. In such circumstances, the simplest strategy is one that identifies and evaluates all the plausible interpretations of an argument.

Visual metaphors are common in works of art, political propaganda, and political cartooning. One popular motif depicts politicians with a growing Pinocchio nose, suggesting that they are, like the childhood hero, preposterous liars (see Tseronis and Forceville 2017). In cases such as this, visual images can have rhetorical as well as logical significance, allowing arguers to convey their arguments in rhetorically powerful ways.

2.4 Modes of Arguing

Informal logicians who advocate for systems of informal logic that broaden the language of argument from NL to NL+ sometimes expand the standard notion of argument even further, beyond verbal and visual arguments, to make room for other ways of arguing.

The role of non-verbal carriers of meaning in real life discourse allows many different semiotic modes to contribute to informal arguments. In view of this, some argue that a fully comprehensive account of argument must include a “multimodal” account of meaning which recognizes many different modes of arguing (see Groarke 2015 ). The latter may employ gestures, facial expressions, sounds of different sorts, tastes, smells, musical notes, and a host of other non-verbal phenomena.

Groarke 2018, Kišiček 2018, and Eckstein 2018 have investigated “auditory” (or “acoustic”) modes of reasoning that depend on non-verbal sounds. Examples are situations in which the sound of a siren is pointed to as evidence that the police are on their way, or the sound of an automobile engine (or an irregular heart) is the basis of an inference to the conclusion that it has a leaky valve.

Other modes of arguing invoke the senses in other ways. In 2019, Space Cargo Unlimited and the University of Bordeaux’s wine institute (the ISVV) sent fourteen bottles of Château Petrus to the International Space Station to determine how a year in space would affect their taste and character. A year later, the wine returned to earth where it was analyzed. A key element of this analysis was a blind tasting conducted by 12 professional tasters who compared the wine from space to bottles of the same vintage which had remained on earth. The sommeliers concluded that the wine which had been in space had a different, distinct (“more evolved”) taste, inferring their conclusion from their two tastings (which functioned as ‘taste premises’).

Here is another example from a wine tasting.

EXAMPLE 5: A wine steward attempts to convince a customer that Napa Valley “Frogs Leap PS 2015” is an exceptional Petite Syrah by quoting high praise in a wine guide, and by handing them a glass, inviting them to taste it.

In this case, the steward provides evidence for their claim that Frogs Leap PS 2015 is an exceptional Petite Syrah in two ways: (i) via a verbal premise that cites the authority of a wine guide, and (ii) via a taste test that aims to support this conclusion. In the first case, the result is a verbal appeal to authority, in the second an argument by taste.

In real life arguing different modes are often mixed. In the case of verbal arguments, the meaning of oral arguments is often notable for its dependence on the sound of the human voice — which can convey meaning above and beyond that implied by words. As Gilbert (1997) notes, uttering the sentence “Fine, fine, you’re right, I’m wrong, we’ll do it your way,” “can indicate agreement with what has been said if presented flatly and intended sincerely, or, if accompanied by an expression of anger, can mean that the respondent does not agree at all, but is capitulating.” (pp. 2–3) Kišiček 2014 has highlighted the important role that the paralinguistic features of oral arguments play in many instances of verbal argument.

Gilbert 1997 was the first informal logician to suggest that there are different modes of arguing that need to be distinguished. His “multi-modal” theory of “coalescent” argument accepts the traditional conception of argument as one mode, adding to it “emotional,” “visceral” (physical) and “kisceral” (intuitive) modes of arguing. He pairs this with a very broad account of arguing which understands it as an attempt to resolve conflicting attitudes, beliefs, feelings and intuitions in a way that brings about the “coalescence” of competing points of view.

According to Gilbert’s account, an argument may consist of sentences and/or expressions of emotion, physical demonstrations and difficult to define intuitions. This allows a forlorn look or tears to count as premises in an argument insofar as they provide evidence that promotes coalescence (and inference in this broad sense). As Gilbert argues, his non-traditional modes of arguing may, in real life situations, provide effective ways of resolving the disagreement that gives rise to argument.

Gilbert’s account of modes radically expands our understanding of argument beyond “language” as it is traditionally conceived. In an account of the “anthropology” of argument, Tindale 2021 defends the alternative “logics” this makes possible. In doing so, he promotes informal logics that recognize verbal arguments (and in this sense L ) but add to it a much broader range of everyday communication which can convey the substance of an argument via expressions of emotion, physical actions (including non-verbal means of communication like so called “body language”), and difficult to define intuitions. This expands the language of argument far beyond words and sentences, in a way that maximizes the breadth of L+ .

The ultimate goal of informal logic is normative: i.e. systems of logic that provide us with tools that can be used to evaluate real life arguments and the key components they contain. Because real life discourse often fails to present the latter clearly, most systems of informal logic prepare the way for argument evaluation by explicitly identifying an argument’s premises, conclusions, and inferences. The process of doing so is commonly called “standardizing” ( S in the BLAST definition).

In the process of standardization, informal logics aim to untangle issues that obscure the structure and content of real life arguments. Arguments in ordinary discourse are, for example, frequently vague, ambiguous or in other ways unclear. Premises and conclusions can be conveyed by rhetorical questions (“Can anyone seriously believe...?” “Could the defendant have been in two places at once?”) and the key components of an argument may be interspersed with irrelevant digressions and repetition. When we extract an argument from the context in which it occurs, it can be important to recognize what is implicit but relevant at the same time that we discard what is explicit but irrelevant.

Standardizing clarifies the structure of an argument in ordinary discourse by:

• discarding irrelevant and distracting digressions, repetition, and remarks (“noise”) which do not play a role in the reasoning the argument contains;
• restating the content of rhetorical questions and other stylistic devices that may obscure the meaning of the argument’s components;
• clarifying incomplete, vague or ambiguous claims and utterances; and/or
• recognizing components of the argument which are not explicitly expressed.

Systems of informal logic may standardize arguments in a variety of ways. In its simplest form, a standardized argument is a list of premises and a conclusion (the argument’s inference is the implicit move from the premises to the conclusion). EXAMPLE 1 above can be standardized as follows.

Premise : [Small businesses] provide opportunities for entrepreneurs and create meaningful jobs with greater job satisfaction than positions with larger, traditional companies. Conclusion : Small businesses are important.

In this example, the word “because” functions as an “inference indicator” which tells us that the claim that follows is a premise offered in support of the conclusion which precedes it. In other cases, words like “for,” “given that,” “since,” are ways of introducing premises, while words like “so,” “hence,” “thus,” “therefore,” are used to introduce conclusions.

Verbal inference indicators are an important, but not necessary or sufficient, sign of argument. For indicator words can be used in other ways (“because” may indicate an explanation rather than an argument, a causal connection, emphasis of some sort, a temporal order, etc.), and are not necessary when a context makes it clear that someone is providing reasons for a conclusion.

3.1 Implicit Premises and Conclusions

One issue that is frequently addressed in standardization is an argument’s dependence on premises and conclusions which are assumed but not explicitly stated.

The following report from the New Hampshire Rockingham News (30/8/2002) comments on a court case which sent the organizer of dog fights to jail for cruelty to animals.

EXAMPLE 6: A co-ordinator for the Humane Society supported a prison sentence, claiming that the minor penalties normally associated with misdemeanor convictions are not a sufficient deterrent in this case.

We can standardize the co-ordinator’s argument as follows.

Premise : The minor penalties normally associated with misdemeanor convictions are not a sufficient deterrent in this case. Implicit Premise 1 : Penalties for crimes should have a deterrent effect. Implicit Premise 2 : Prison is a sufficient deterrent. Conclusion : A prison sentence, but not the minor penalties normally associated with misdemeanor convictions, is appropriate.

It is important to recognize the assumption which is rendered as Implicit Premise 1 (which is, in Toulmin’s words, “a warrant”) for it is a claim that the argument depends on when the arguer concludes that the penalties normally associated with misdemeanors are not a sufficient deterrent in this case. The remaining part of the conclusion — the suggestion that a prison sentence is appropriate — depends on Implicit Premise 2 , which recognizes the further assumption that this will have a deterrent effect.

Recognizing the argument’s implicit premises prepares the way for argument evaluation, for they, like the argument’s explicit premise, need to be evaluated when the argument is assessed. If we reject the implicit premises (by, e.g., arguing that the goal of criminal penalties should be retribution, not deterrence), then the argument fails to provide convincing evidence for its conclusion.

Arguments with implicit premises or conclusions are recognized in ancient discussions of enthymemes : syllogisms with unstated premises. A contemporary example is American Vice-President Dick Cheney’s defense of the Bush administration’s decision not to try foreigners charged with terrorism offenses as prisoners of war (something that would guarantee legal protections for those accused of terrorism).

EXAMPLE 7 (from a report in the New York Times , 15/11/2001): “The basic proposition here is that somebody who comes into the United States of America illegally ... is not a lawful combatant.... They don’t [therefore] deserve to be treated as a prisoner of war.”

We can standardize the argument as:

EXAMPLE 8: Premise : Somebody who comes into the United States of America illegally ... is not a lawful combatant. Implicit Premise : Someone who is not a lawful combatant doesn’t deserve to be treated as a prisoner of war. Conclusion : They don’t deserve to be treated as a prisoner of war.

As in many other cases, the argument’s implicit premise identifies the link that ties the explicit premise to the conclusion. When we evaluate the argument, it raises a number of questions. How should a “lawful combatant” be defined? Why are combatants who illegally enter a country for the purpose of war (in undertaking surveillance or going behind enemy lines) widely recognized as prisoners of war? What are our moral obligations to combatants, lawful and unlawful?

In other enthymemes, the conclusion of an argument may be unstated. In a debate over the question whether witnesses to a crime can be trusted, an arguer might state: “ They are friends of the accused, and no friends of the accused can be trusted.” Such claims clearly suggest that “ They cannot be trusted,” a claim that needs to be recognized as an implicit conclusion in an attempt to standardize and evaluate the argument.

As in the case of verbal arguments, implicit premises and conclusions play an important role in many visual and multimodal arguments. In EXAMPLE 9 (below), the title “Just Add Vodka” is superimposed over a gigantic bottle of vodka pouring its contents on the scene below. Outside the vodka splash, one sees a sleepy hamlet. Inside the vodka splash, it is transformed into a bustling cityscape which boasts skyscrapers and a nightlife with lights, people, nightclubs, bars, and restaurants.

The image in this advertisement is a visual metaphor which suggests that vodka can transform one’s life in the way that it transforms the scene in the advertisement, turning the (dreary) life one lives in a sleepy hamlet into the kind of exciting nightlife one finds in a cosmopolitan urban center. Insofar as this message is featured in an advertisement, we can plausibly understand this message as a proposed reason to buy the vodka in question.

We might standardize the argument this implies as follows.

EXAMPLE 9: (Visual) Premise : If you drink our vodka, it can transform your night life in the way it transforms the village in the photograph: into an exciting major city. Implicit Premise : A life of urban excitement is preferable to the quiet life of a village. Conclusion : You should “Just Add Vodka” to your life.

I have summarized the first premise in the argument in a way that refers to the image because it is difficult to fully capture the (almost magical) transformation the advertisement promises if we try to translate it into words. The implicit premise in the standardization is a key part of the argument because it is a key assumption made in the move from the (visually) explicit premise to the conclusion. So understood the argument can be analyzed and evaluated as an argument which has a questionable explicit and implicit premise (and an inference which is an instance of the fallacy “Affirming the Consequent”).

The attempt to identify implicit premises or conclusions in an argument can raise some significant theoretical questions when it is standardized. All arguments rely on many assumptions, raising the question whether and when and how they should be recognized. In cases in which it is clear that an unstated premise or conclusion needs to be recognized, it can often be interpreted in different ways.

One principle that many systems of informal logic use to choose between alternative interpretations of implicit argument components is the “Principle of Charity.” It favors an interpretation of an argument which makes it as credible as possible. In many situations, this can best be accomplished by attributing it a “logical minimum,” understood as the weakest implicit component needed to successfully connect the argument’s premises to its conclusion.

3.2 Key Component Tables and Diagrams

Standardizing arguments by listing their premises and conclusions is one way to delineate the content of an argument and prepare it for evaluation. But standardizing of this sort has a major shortcoming, for it does not distinguish between different kinds of inferences an argument may contain. One way to address the issues that this raises is by standardizing an argument with a table that catalogues an argument’s premises and conclusions (a Key Component or “KC” table) and combining it with an argument diagram (a “mapping”) that depicts the structure of its inferences.

In EXAMPLE 10 (below), I have used this method to standardize an argument that Kretzmann uses in his account of the medieval philosopher William of Sherwood, where he concludes that it is likely that William was a Master at the University of Paris. The first column of the KC table lists the premises and conclusion of the argument; the second assigns them their role as premise or conclusion; the third lists the source from which they are derived. The diagram that follows depicts the relationships between the argument’s key components, using arrows to indicate the inferences it includes.

This standardization shows that the Sherwood argument is supported by three “convergent” premises which provide three independent reasons that support the argument’s conclusion in different ways.

In other instances of argument, two or more “linked” premises combine to support a conclusion with a single inference. The argument “The murderer was very strong, so George cannot be the murderer.” is an enthymeme which assumes that “George is not very strong.” Using square brackets ([ ]) to indicate this implicit component, we can standardize the argument with the following KC table and diagram. In this case, the linked premises are indicated with a plus sign (“+”) that connects them in the diagram. It indicates that they support a conclusion (only) when combined.

The use of KC tables and diagrams is not limited to purely verbal arguments. When arguments have non-verbal key components, visual and multimodal premises and conclusions can be recognized in a key component table by ostension, or by reproducing them in some way. Once they are identified in a KC table, the inferences such arguments depend on can be mapped in standard ways.

The following table and diagram standardizes EXAMPLE 3, which contains an inference from three linked premises (two visual and one verbal) to the conclusion that there is water on the planet Mars.

KC table are not the only way to diagram the structure of real life arguments. Diagramming (mapping) has its own history, which incorporates many different ways of diagramming arguments. The usefulness of diagramming is already recognized in Whately 1826 and, in the early twentieth century, in Wigmore 1913, who develops a form of mapping (“evidence charts”) designed to portray and analyze complex chains of judicial reasoning.

The development of informal logic has kindled a renewed interest in different kinds of diagrams which are supported by the development of associated software (Rationale, Reason!Able, Araucaria, Athena, Compendium, Theseus) and online aids (Debate Mapper, TruthMapping.Com, Argunet, Agora).

3.3 Supplemented Diagrams

KC tables and diagrams prepare the way for argument evaluation by clarifying the internal structure and content of an argument. Other aspects of an argument that may need to be considered in argument assessment can be included in a “supplemented” diagram which adds an account of the context in which it is embedded. Three aspects of arguments merit note in this regard.

The first is the audience to which an argument is addressed. Most real life arguments are used in an attempt to convince some intended audience of some point of view. In view of this, successful arguments must be built with this in mind.

A convincing argument for the conclusion that the United Nations cannot be trusted must address different issues when it is directed at a Chinese, Norwegian, Kenyan, Israeli, Swiss, Palestinian, etc. audience. As rhetoric has emphasized since its beginnings, this means that successful arguers must construct their arguments in ways that recognize the beliefs, attitudes and values of their intended audience (and in this sense ‘speak’ to them). Tindale (1999, 2004, 2010) has imported this notion into informal logic, advocating an informal logic that incorporates an analysis of audience.

A second contextual factor relevant to the evaluation of an argument is the goal of the arguer. As Hitchcock 2002 points out, acts of arguing may make a declaration (“The evidence shows that you committed an assault, so I find you guilty as charged.”); command or make a request (“You were there, so you must tell us what happened.” “The children are shivering, so please close the door.”); make a promise (“I know it matters to you, so I promise to go tomorrow.”); express a sentiment (“What we did was inexcusable, so we beg your forgiveness”); and function in many other ways.

As Pinto and Gilbert have emphasized, this means that a successful argument (which is successful in the sense that it accomplishes the arguer’s purpose in presenting the argument), may produce a withholding of assent (or full assent) to some proposition, a particular attitude, an emotional state like fear or hope, or a certain kind of behavior (by, e.g., as when an argument demands that people take up arms against a foe or take action in support of social change). When one bargains, the goal of argument is not truth, but a bargain that serves one’s interests. As Hoffman 2016 notes, an argument may not aim to resolve disagreement, but to promote reflection and the raising of important questions.

The different goals arguer’s try to achieve via argument may make their success and legitimacy turn on norms and rules that add to (or subtract from) the traditional strictures that guide argument evaluation. In some circumstances, it makes ultimatums, exaggerations, threats and insults a permissible element of arguing. In sharp contrast, they are unacceptable in attempts to determine what is true from a scientific point of view, where such behaviors are instances of the fallacy ad baculum .

Walton 2007 accommodates the different goals associated with real life arguments by distinguishing between different kinds of dialogues in which arguing occurs. The rules for a particular kind of dialogue define what types of argumentative moves are allowed, what kinds of questions and responses are permitted, and what norms arguments must adhere to.

The seven basic types of dialogue he distinguishes can be summarized as follows.

In dialogues of inquiry, arguments are used as tools in an attempt to establish what is true. So understood, arguments must adhere to strict standards that determine what counts as evidence and counter-evidence for some point of view. In eristic dialogue, arguing is combat and the aim is to vanquish one’s opponent (and humiliate them, ideally by wowing one’s audience with one’s mental gymnastics). In doing so, sophistical tricks and fallacious reasoning are welcome if they serve this end.

Walton’s dialogue typology leaves room for more narrowly defined kinds of dialogue. Collective bargaining is a specific kind of negotiation dialogue which is governed by legal rules and well established practices that very precisely delineate what is and is not allowed in bargaining. Different subdialogues are associated with different norms, rules and practices.

A third contextual factor that may warrant comment in a supplemented diagram is the dialectical context in which an argument occurs. In his account of argument, Johnson 2000 distinguishes between the “illative” core of an argument and the argument’s “dialectical tier,” understanding the former as a “proto-argument” which consists of a set of premises offered in support of some conclusion. It is the kernel of an argument, but he considers it an argument in the full sense only if it fully engages the dialectical tier, considering alternative points of view, addressing objections to the conclusion it proposes.

The ultimate goal of informal logic is normative: an account of argument and systems of informal logic that can be used to determine when and whether real life arguments are strong or weak, good or bad, convincing or unconvincing. Standardizing prepares arguments for such assessment. This makes T in the BLAST definition — the tools and methods which are used to test argument strength — the most important defining element in a system of informal logic.

Almost all informal logics understand a good (strong) argument to be an argument with “acceptable” premises and a “valid” inference — i.e. a conclusion that follows from them. Hansen 2012 has argued that informal logic should follow classical logic, and not concern itself with the assessment of premise acceptability, but its engagement with real life arguments (and the desire to evaluate them in a fulsome way) has produced a field that includes this within argument evaluation. In this and in other regards, systems of informal logic adopt many different approaches to argument assessment.

4.1 AV Criteria

In classical logic, an argument is (deductively) valid if it is impossible for its premises to be true and its conclusion false. On this account, the ultimate aim of arguing is a “sound” argument: i.e. a valid argument with true premises.

Within informal logic, the simplest criterion for good arguments is an informal analogue of soundness. It understands a good argument to be an argument that justifies its conclusion by providing good (strong, credible, etc.) reasons for believing it. Within the argument, this implies premises which are “acceptable” and a conclusion that follows from them. We can summarize this basic criterion as T = { A , V }, where A is an account of premise acceptability, and V is an account of informal validity which determines when a conclusion follows from premises in a way that is approved of (deductively, inductively, conductively, and/or abductively, etc.).

Following Johnson and Blair (1977, 1994), many systems of informal logic adopt an ARS version of these AV criteria, making “Acceptability, Relevance and Sufficiency” the requirements for good argument. On this account, premises are acceptable when they are true or acceptable in some other way; relevant when they provide some (i.e. any) support for the conclusion of the argument; and sufficient when they provide enough support to warrant its acceptance — as likely, true, plausible, etc.

Premise Acceptability

Within informal arguments, premises may be acceptable in a variety of ways. In many circumstances, they are acceptable if they are likely true and unacceptable if likely false.

It is worth noting that this truth criterion can be expanded to apply to visual premises. An image functioning as a visual premise may, for example, be evaluated as a “true” or “false” depiction of what it represents. A photograph or an image may be unacceptable because it is untrustworthy or categorizes a situation in a misleading way. Photographs are often ‘doctored’ or in other ways designed to present things in ways that do not accurately reflect what is photographed. Other kinds of multimodal premises can be understood as likely true to the extent that they are a reliable basis for an inference.

In some kinds of dialogue — in the exchanges that characterize negotiation, bargaining, eristic, and persuasion — acceptable premises may not need to be true. In bargaining (“haggling”) a buyer may claim that “I will not give you a penny more than $300 for that lamp” as a premise in support of the conclusion that the seller should agree to a lower price. This counts as an acceptable premise even if it is an idle threat that the buyer will never carry out, for threats of this sort are an acceptable element of the arguments that take place in this kind of dialogue.

In other cases, informal logics use acceptability rather than truth as a criterion for judging premises in contexts in which it is difficult to judge premises as true or false. In such cases, acceptable premises may be plausible (or exploratory) hypotheses, claims that can only be said to be generally accepted or assumed, or ethical or aesthetic judgments which are not easily categorized as true or false.

In still other circumstances, truth may be required for acceptability, but only one of a number of conditions that must be satisfied. Even when a premise is true, it may be unacceptable because it violates the rules of interaction that govern the dialogue in which it is embedded. In a legal proceeding or a formal hearing, premises and arguments must not entertain premises that violate rules of procedure.

In situations in which arguments are attempts to convince a specific audience of a conclusion, an acceptable premise may need to be true, but also acceptable to the members of this audience. As Aristotle suggests in the Rhetoric , successful arguments may need to have premises that are in keeping with the pathos of an audience (and do so in a way that does not undermine the character — the ethos — of the arguer). As Gilbert 1997, 2014 has emphasized, there are many real life circumstances in which the emotional acceptability of a premise is required for argument success.

One of the first VR productions by the New York Times was “Kiya,” a production which recreated an incidence of domestic abuse in an attempt to provide support for the importance of attempts to address issues of domestic violence. Its producer describes it as an attempt to use “the immersive power of virtual reality: its ability to generate intense empathy on the part of the viewer; to wring from the audience the intense emotional connection that these stories deserve” (NYT, Jan 21, 2016).

Inference Validity

In its attempt to account for a broad range of real life arguing, informal logics have expanded traditional notions of premise acceptability. Something similar has happened in the case of inference validity. The end result is an expansion of both sides of the AV criteria for good argument.

In the case of inference validity, this expansion has been accomplished by treating deductive validity as one variant of validity, and by recognizing other “defeasible,” non-deductive ways in which premises may entail conclusions. Govier 1987 dubs the deductive/inductive distinction as “the great divide,” emphasizing the latter over the former. Sometimes informal logic systems understand inductive arguments narrowly, as inductive generalizations. Sometimes more broadly, as arguments which have premises that imply that a conclusion is (only) probable or plausible, leaving open the possibility that it is false.

“Conductive” arguments support their conclusions by accumulating non-decisive reasons in their favor. They are valid when they collect enough reasons to warrant their conclusions. In a particular case, different elements of evidence may suggest but not prove that someone charged with murder is guilty but make the conclusion likely if enough evidence of this sort is accumulated (a witness claims he pulled the trigger, the ballistics report shows that the bullet came from a gun he owned, he wrote an e-mail saying he would “get” the victim, etc.).

Strong “abductive” arguments are convincing instances of “inference to the best explanation” (see Harman 1965). They recognize some facts, point out that they are entailed by some hypothesis, and conclude that the hypothesis is true. Taken at face value, abductive arguments appear to be instances of the deductive fallacy “affirming the consequent,” but play an important role to play in medical, scientific and legal inquiry (see Walton 2004).

4.2 Fallacy Theory

AV criteria are in many ways an extension of the notion of good argument enshrined in classical logic. In the search for ways to deal with real life arguments, some informal logicians have moved in a different direction, reviving fallacy theory as an alternative. Hamblin 1970 has become a touchstone for moves in this direction.

Systems of informal logic that rely on fallacies test arguments by asking whether their proponents are guilty of fallacious reasoning. While there is no agreed-upon taxonomy of fallacies, many canonical fallacies have been emphasized in the analysis of informal arguments. They include formal fallacies like affirming the consequent and denying the antecedent; and informal fallacies like ad hominem (“against the person”), slippery slope, ad baculum (“appeal to threat or force”), ad misericordiam (“appeal to pity”), “hasty generalization,” and “two wrongs” reasoning (as in “two wrongs don’t make a right”). The systems of informal logic taught in textbooks often add specialized variants of the standard fallacies (“misleading vividness” designates the misuse of vivid anecdotal evidence in hasty generalizations, and so on.)

Woods and Walton 1982 and Hansen and Pinto 1995 contain detailed discussions of the definition, analysis and assessment of fallacies. In argumentation theory, van Eemeren and Grootendorst 1992 propose a “pragma-dialectical” account of fallacies which treats them as violations of rules that govern critical discussion -- dialogues that attempt to resolve a difference of opinion. Battersby and Bailin 2011 view fallacies as patterns of argument patterns “whose persuasive power greatly exceeds its probative [i.e. evidential] value,” making fallacies errors in reasoning that ordinary arguers are attracted to in view of their rhetorical appeal.

Some fallacies — e.g., equivocation and begging the question (i.e. circular reasoning) — highlight important issues that frequently interfere with real life arguing, but fallacy theory has been criticized when it is adopted as a general account of argument. The issues this raises include its unsystematic nature, disagreements about the definition and nature of specific fallacies, and the emphasis that fallacy theory places on faulty reasoning rather than good argument. Hitchcock (1995, 324) writes that the idea that we should teach reasoning by fallacies is “like saying that the best way to teach somebody to play tennis without making the common mistakes is to demonstrate these faults in action and get him to label and respond to them” (see Feldman 2009).

The theoretical issues raised by fallacy theory are compounded by instances of traditional fallacies which have a reasonable role to play in real life arguing. Appeals to pity and other appeals to emotion have, to take one example, a legitimate role to play in moral, political and aesthetic debate. The following examples highlight other circumstances in which arguments which fit the definition of a traditional fallacy cannot be so readily dismissed.

EXAMPLE 12: A remark from a Danish television debate over the question whether the Danish church should be separated from the Danish state (Jorgensen 1995, 369): “You should not listen to my opponent. He wants to sever the Danish church from the state for his own personal sake.” This seems a classic example of ad hominem , Kahane 1995 (p. 65), describing it as a fallacy that occurs when an arguer attacks “his opponent rather than his opponent’s evidence and arguments.” But this is an accusation of conflict of interest which cannot be dismissed out of hand. If there is reason to believe that an arguer favors a point of view because they have something to gain from it (say, the purchase of a company in which they own shares), this does raise questions about the extent to which their arguments should be entertained. EXAMPLE 13: Martin Luther King Jr., influenced by Gandhi, argued that one can justifiably break laws in a struggle for social justice. Such arguments play a central role in the civil rights movement. They cannot be summarily dismissed, though they appear to be clear cases of “two wrongs make a right.” EXAMPLE 14: The argument that “the attempt to use military force to put an end to terrorism is wrong because it will take us down a slippery slope that will end in improper interference in the affairs of independent states” cannot be dismissed because it is an instance of slippery slope reasoning. If it is true that some action will precipitate a chain of consequences that lead down an alleged slippery slope, this is a good reason to question it.

Examples of this sort have forced careful accounts of fallacies to make room for reasonable arguments which share the form of traditional fallacies.

In doing so, it is helpful to distinguish between fallacies which do and do not have non-fallacious instances. Equivocation, post hoc ergo propter hoc , non sequitor and hasty generalization are commonly classified as forms of argument that are inherently mistaken. In contrast, traditional fallacies like ad hominem , two wrongs reasoning, guilt by association, and appeal to pity are patterns of reasoning which can, when they are constructed in the right way, play a legitimate role within real life reasoning (and are, in view of this, sometimes treated as argument schemes rather than fallacies).

4.3 Natural Language Deductivism

Natural Language Deductivism (“NLD”) is an approach to informal reasoning that retains classical logic’s focus on deductive validity (see Groarke 1999, and Govier 1987 , who develops an initial account NLD, but ultimately favors a more radical break from classical logic). It suggests that we should interpret informal arguments as attempts to create deductively valid inferences which can be analyzed and assessed accordingly. In a deductivist system of informal logic, the V in the AV criteria for good arguments is this classical notion of validity.

NLD has frequently been rejected on the basis of the common, but mistaken, notion that deductively valid arguments must have certain conclusions — a misconception that seems founded on deductive validity’s historical connections to formal logic and mathematics (see Groarke 1999). It is true that ordinary arguing rarely satisfies the strict proof procedures they imply, but deductive validity is not restricted to this compass and there are many instances of ordinary argument which are clear examples of deductively valid argument.

In cases of deductive reasoning, the conclusion of an argument need not be certain, but only as certain as the premises, creating ample room for conclusions which are merely likely, plausible, or probable. EXAMPLE 15 is taken from a radio commentary on population growth.

EXAMPLE 15: The population of the world will grow from 6 to 9 billion in the next fifteen years so we will, if we are to provide sufficient food for everyone, need to find a way to provide food for an additional 3 billion people.

In this case, the premise of the argument is not certain, but reasonably thought to be true — because it was (in the commentary) backed by an extrapolation from well established population trends. The deductively valid inference based upon it makes it reasonable to judge the conclusion of the argument true as well, though it is not certain, as all predictions about population growth are, at best, plausible conjectures.

NLD’s plausibility as a general theory of argument turns on its account of arguments which are not prima facie deductive. Faced with arguments of this sort, it preserves the deductivist approach by attributing an implicit premise (essentially, a deductive warrant) to such arguments in a way that deductively connects an argument’s premises to its conclusion. Typically this is an “associated” conditional of the form “If P, then C” where P is the argument’s premises and C is its conclusion.

A 2015 blog by a professional dietician (Dr. Cristina Sutter) criticizes arguments that justify the claim that garcinia cambogia is a miracle weight loss pill by appealing to the authority of the popular television personality “Dr. Oz.” — instances of the reasoning “Dr. Oz Says It, So It Must Be True.” We can standardize the pattern of argument she criticizes as:

EXAMPLE 16: Premise : Dr. Oz says [that gracinia cambogia is a miracle weight loss pill]. Conclusion : This must be true.

If one judges only by the explicit premise in this argument (“Dr. Oz says...”), this is not a deductively valid argument, for it is obvious that the premise could be true and the conclusion false: Dr. Oz could say gracinia cambogia is a miracle weight loss pill and be wrong. That said, anyone using this argument must assume an associated conditional which can be understood as an implicit premise, allowing us to standardize the argument as:

Premise : Dr. Oz says [that gracinia cambogia is a miracle weight loss pill]. Implicit Premise : If Dr. Oz says this, it must be true. Conclusion : This must be true.

So understood, the Dr. Oz argument is deductively valid, but not sound, as it is a valid argument with a problematic implicit premise.

NLD deals with inductive generalizations in a similar way. Consider the following example from a conversation about French men.

EXAMPLE 17: “French men are fastidious about their appearance. I have worked with many and this was what I found.”

In this example, the move from the premise to the conclusion of the argument assumes that the sample of French men the arguer is familiar with are a representative sample of French men. If this is not likely, then the sample does not provide good reasons for concluding that French men are, in general, as fastidious if they are. If we recognize this assumption as an implicit premise when we standardize the argument, then the argument is deductively valid, for a representative sample is a subset of a population that accurately reflects the characteristics of the larger group.

In this way, NLD turns the uncertainty that characterizes inductive generalizations (and other forms of informal validity) into uncertainty that is connected to an associated conditional which warrants the move from an argument’s premises to its conclusion. This does not eliminate such uncertainty, but maintains it as a key consideration in argument evaluation, for it makes the status of this warrant an essential element of premise acceptability.

In favor of NLD, it has been argued that reconstruction of many arguments it proposes is a dialectically useful way to make explicit the key assumptions that arguments depend on, and frees us from the need to distinguish between different kinds of validity in ways that can be problematic when they are applied to real life arguing. The pragma-dialectical account of indirect speech acts (Eemeren and Grootendorst 2002, Groarke 1999) provides a way to reconstruct arguments as deductive arguments when NLD requires it, though Johnson 2000 and Godden 2004 argue that NLD is an artificial theory which forces informal arguments to adhere to an overly restrictive model of inference.

4.4 Argument Schemes

Argument (or “argumentation”) schemes are recurring patterns of reasoning. Once identified they can be used to evaluate an argument which is instance of a scheme, or as a template or recipe arguers can use when they construct an argument which is an instance of a scheme. Walton, Reed and Macagno 2008 provide a compendium of 96 schemes. Wageman has developed a Periodic Table of Arguments which provides a systematized account of basic schemes.

Rules of inference like modus ponens and modus tollens can be understood as deductive schemes. Other schemes commonly used in ordinary arguing include Argument by Sign, Argument by Analogy, Argument by Example, and Slippery Slope Reasoning. Dove 2016 and Groarke 2019 have shown how visual arguments with non-verbal visual elements may be instances of common schemes, and have identified some schemes which are inherently visual.

The most common approach to argument schemes combines a pattern of argument with a set of “critical questions” with which it is associated. The scheme Argument from Authority (“Appeal to Authority,” “Appeal to Expert Opinion”) and the critical questions it raises can be formalized as follows.

A is an authority in domain D. A says that T is true. T is within D. (Therefore) T is true.

Critical questions : 1. How credible is A? 2. Is A an authority in domain D? 3. What did A assert that implies T? 4. Is A someone who can be trusted? 5. Is T consistent with what other experts assert? 6. Is A’s assertion of T based on evidence?

Prakken 2010b understands argument schemes as inference rules, some critical questions ensuring the truth of an argument’s premises, others ensuring that the context of the inference is appropriate.

Another approach to schemes builds the answers to critical questions into a ‘full’ definition of the scheme, treating them as required premises in convincing instances of the scheme. Taking this approach, the scheme Argument from Authority can be defined as follows.

A is a credible authority in the domain D. A asserted X, which implies T. A can be trusted and T is within domain D. T is consistent with what other experts in domain D assert. A’s assertion of T is based on evidence. (Therefore) T is true.

The critical question approach to schemes suggests that a credible argument from authority must include acceptable premises of the form outlined in the definition of the scheme, and is valid if it is backed by answers to the scheme’s critical questions. Taking the ‘full’ approach, a valid argument from authority must include the premises that define it as as a good argument as explicit (or possibly implicit) premises. In both cases, the result is an account of premise acceptability and validity which is tailored to specifically apply to arguments from authority.

Different argument schemes are a refinement of general AV criteria, creating specific criteria which can be applied to different kinds of argument.

When a student essay claims that “we should not stockpile nuclear weapons” because Einstein told us that this would lead “to destruction even more terrible than the present destruction of life” (EXAMPLE 18), this is an appeal to authority which invokes Einstein as an authority. In order for it to be a convincing argument from authority, it would need to fully satisfy the conditions outlined in our definition of the scheme Argument from Authority .

The attempt to satisfy the requirements this implies produces a version of the argument which can be summarized as follows.

EXAMPLE 18 expanded to satisfy the criteria for a convincing argument from authority: 1. Einstein (A) is a credible authority on nuclear weapons (D). 2. Einstein (A) asserted that the stockpiling of nuclear weapons would precipitate “destruction even more terrible than the present destruction of life” (X), which implies that we should not stockpile nuclear weapons (T). 3. Einstein (A) can be trusted and questions about stockpiling nuclear weapons (T) are questions about nuclear weapons (D). 4. The claim that we should not stockpile nuclear weapons (T) is consistent with what other experts on nuclear weapons (D) assert. 5. Einstein’s (A’s) assertion that we should not stockpile nuclear weapons (T) is based on evidence. 6. (Therefore) We should not stockpile nuclear weapons (T).

This attempt to satisfy the conditions for a good instance of argument from authority fails because it produces a number of problematic premises. Other experts disagreed (and continue to disagree) with Einstein’s suggestion that it is a mistake to stockpile nuclear weapons. More fundamentally, the proposed argument is founded on too loose an account of nuclear weapons as a domain of expertise. Einstein is a renowned expert on nuclear physics but this it does not make him an expert on the social and political issues raised by nuclear weapons. This is something that a convincing version of the argument would have to establish.

In some ways, the scheme approach to argument assessment rectifies problems that arise in systems of informal logic that adopt the fallacy approach to argument evaluation. For traditional fallacies which have non-fallacious instances can be understood, not as fallacies, but as argumentation schemes which are legitimate forms of reasoning when they are properly employed. Fallacy definitions can be turned into scheme definitions by identifying a list of critical questions (or required premises) that specify what is required to make the arguments in question valid.

Ad hominem is a case in point, for there are many instances in which criticisms of an arguer (rather than their position) are a reasonable way to cast doubt on their views. We can specify when this is so by listing critical questions that determine whether this is so in a particular case of argument. The basic question that must be asked is whether there is a good reason why the arguer’s views should not be taken seriously — a question that subsumes the more specific questions whether they have repeatedly shown poor judgment, are biased, lack expertise in the area in question, or are for some other reason an arguer who should not be listened to.

Treated in this way, ad hominem is a legitimate scheme of argument, but there are (as there are in the case of all schemes) many situations in which ad hominem arguments are poor instances of the scheme. In this and many other cases, traditional fallacies can be regarded as deviations from an inherently correct scheme of reasoning.

4.5 Testing Systems

Most informal logics combine different ways of evaluating arguments. In this way, T in a particular system tends to be some combined set of tools that can be used in this endeavor. In most cases, T = { F , AV , AS }, where F is some list of fallacies, AV is some kind of AV criteria (say, the standard ARS criteria) and AS is some set of argumentation schemes.

But systems of informal logic can accommodate other, less common criteria for deciding whether arguments are good or bad, strong or weak. A system might, for example, incorporate criteria which are founded on a virtue-based approach to argument (see Virtues and Arguments) , on feminist principles, or on notions derived from rhetoric, theories of communication, or other cognate fields.

Informal logic’s attempt to understand argument as it occurs in a broad range of real life situations continues to evolve in a way that is influenced by the study of real life reasoning that takes place within the broader scope of argumentation theory.

One cognate field of note is Artificial Intelligence (AI). It relies on step by step accounts of informal reasoning in a wide array of contexts. Informal logics provide this in a general way that has influenced the attempt to model argumentation between agents in multi-agent systems which mimic or assist human reasoning. Computational models have been applied to large-scale collections (‘webs’) of inter-connected arguments, and to reasoning about medical decisions, legal issues, chemical properties and other complex systems. Automated argument assistance functions as a computational aid that can assist in the construction of an argument. Verheij 2014 provides an overview of the issues that this raises.

The development in the empirical study of real life reasoning is the study of argument “corpora” — large collections of argument drawn from natural language discourse. In an early study of this sort, Jorgenson, Kock and Rorbech 1991 analyzed a series of 37 one-hour televised debates from Danish public TV. The debates featured well-known public figures arguing for and against policy proposals. A representative audience of 100 voters voted before and after the debate. Their conclusions were compared with standard notions of “proper” and “valid” argumentation. Other studies consider corpora made up of large databases of selected written texts (see, e.g., Goodwin and Cortes 2010, and Mochales and Ieven 2009).

Argument mining is a subfield of data mining, or text mining (and computational linguistics). It uses software and algorithms that automatically process texts looking for argument structures — for premises, conclusions, argumentation schemes, and extended webs of argument. The texts studied include legal documents , on-line debates, product reviews, academic literature, user comments on proposed regulations, newspaper articles and court cases, as well as dialogical domains. ARG-tech , the Centre for Argument Technology, has played a central role in studies of this sort.

Other research relevant to informal logic has highlighted many ways in which the success of real life arguments depends on aspects of argumentation which are not well integrated into standard systems of informal logic. The latter include an arguer’s ability to draw attention to their argument (using “argument flags” that attract the attention of an intended audience); their personal credibility, ethos , or standing; or their ability to situate their argument within a broader context of debate or dialogue. The study of these and other pragmatic, social, dialectical, semiotic and rhetorical features of arguing will probably play a role in the continued development of informal logic.

The expansion of informal logic to account for an ever broader range of argument is evident in discussions of the use of narratives within argument. In Plato’s Republic , Glaucon uses the mythical story of “The Ring of Gyges” to prove that humans are inherently selfish. In this and many other situations, stories of various kinds (accounts of some historical event, biographies, fables, parables, morality plays, etc) are designed to provide support for some conclusion. It has often been said that a novel or some other work of fiction is an argument for socialism, freedom of expression, or some other value.

One can understand the argumentative use of narratives in a variety of ways: as rhetorical embellishment, as a form of argument by analogy, as implicit generalization (the characters in a story functioning as variables within such generalizations), or reasoning that requires the development of unique standards of argument assessment. According to Fisher 1987, argument itself is best understood as narrative. According to Nussbaum 1990, literature is a way to better understand, and argue about, complex moral situations. Within informal logic, Walton, Reed, and Macagno 2008 identify narrative-based schemes of argument while others continue to debate the role that narratives play in ordinary argument (see Govier and Ayer 2013, Olmos 2014, Plumer 2015).

Informal logic’s interest in real life argument has, from the start, been tied to its interest in the teaching of reasoning skills. In view of this, its interests overlap with fields and disciplines that study education and pedagogy — links manifest in its own influence on critical thinking and the philosophy of education (and movements like “Philosophy for Children”).

Some of the educational issues raised by informal logic are manifest in the development of critical thinking tests which attempt to measure argumentation skills. They are used to test the abilities of students or others and, in a self-reflective way, as an empirical way to test the success of attempts to teach informal reasoning.

Critical thinking (or, even more so, creative thinking) skills are not easily assessed using standardized tests which are designed for large scale use, and typically rely on multiple choice question and answers (see Sobocan 2021). In real life contexts, what counts as good arguing (and thinking) is open ended and unpredictable, dialectical, and influenced by pragmatic and contextual considerations which are difficult to incorporate within standard tests. The California Critical Thinking Test reflects the view of critical thinking elaborated in “The Delphi Report,” commissioned by the American Philosophical Association in 1987, a report that focuses on a narrow range of critical thinking skills which tends to oversimplify the competencies required for good informal argument.

Ennis 2013 provides a comprehensive proposal for dealing with the issues raised by critical thinking tests, and with other challenges raised by attempts to teach critical thinking.

The field of informal logic is a recent invention, but one that continues historical attempts to understand and teach others how to argue. In the Western philosophical tradition, it begins with the sophists’ fifth century boast that they could teach others how to be successful arguers. In Aristotle it is manifest in his systematic account of reasoning, which is expressly designed to teach others how to argue well. Within the history of philosophy, one finds numerous other attempts to formulate accounts of argument that can be used to explain, evaluate, and teach real life reasoning.

The practice of philosophy itself assumes (and frequently develops) an account of argument as it assembles evidence for different philosophical perspectives. Systems of informal logic assume, and often depend upon, the resulting views of reason, rationality and what counts as evidence and knowledge. The philosophical issues in play are tied to complex, unsettled epistemological questions about evidence and knowledge.

Mercier and Sperber (2011) argue that reasoning is a practice which has evolved from, and needs to be understood in terms of, the social practice of argumentation. Johnson 2000 pushes in the opposite direction, arguing that a comprehensive account of argument must be built upon a philosophical account of rationality. Goldman 1999 situates knowledge in the social interactions that take place within interpersonal exchange and knowledge institutions, emphasizing informal argument and the constraints which make it a valuable practice. A 2002 volume of Philosophica on Hilary Putnam’s philosophy suggests pragmatism as an epistemology that best fits informal logic as a discipline.

Some aspects of informal logic raise deep questions that have implications for logic and philosophy. One notable feature of informal logic as it is now practiced is a proliferation of different systems of informal logic which approach the analysis and evaluation of informal reasoning in different ways — employing fallacies, AV criteria, argumentation schemes, methods of formal analysis, and other models of good argument. One implication is a broadening of the conditions for argument felicity.

Other issues are raised by informal logic’s recognition that real life arguments frequently employ visual images, non-verbal sounds, and other non-verbal elements, challenging the traditional assumption that arguments are sets of sentences -- or the propositions (“the bearers of truth value”) that sentences refer to. However one understands visual and multimodal arguments, there is no easy way to reduce them to sets of sentences, for there is no precise way to translate what we see, hear, experience, etc. into words.

In its current state of development, informal logic’s connection to philosophy does not lie in its influence on key philosophical disciplines so much as their influence on it. In North America and elsewhere, informal logic is a field in which philosophers apply theories of argument (rationality, knowledge, etc.) to everyday argument. In keeping with this, philosophers continue to be the core contributors to informal logic; philosophy departments in colleges and universities continue to be the core departments that teach the courses that are its pedagogical focus.

The influence of informal logic courses on the enormous numbers of students that enrol in them require that we at least qualify Rescher’s remark (2005, p. 22) that: “The fact is that philosophy has little or no place in American popular (as opposed to academic) culture... philosophy nowadays makes virtually no impact on the wider culture of North America.” The extent to which informal logic’s attempt to broadly instill good reasoning habits within public education and public discussion and debate is difficult to judge.

Though informal logic addresses many issues relevant to core philosophical disciplines (most notably, epistemology and philosophy of mind; evident in the work of Goldman, Crosswhite, Thagard, and others), it has had limited impact on mainstream approaches to their subject matter. Woods 2000 has speculated on the reasons why. In part, informal logic’s position within philosophy reflects the broader fragmentation of philosophy within North America, Rescher 2005 (p. 4) writing that: “The most striking aspect of contemporary American philosophy is its fragmentation. The scale and complexity of the enterprise is such that if one seeks in contemporary American philosophy for a consensus on the problem agenda, let alone for agreement on the substantive issues, then one is predestined to look in vain.”

In this context, it can best be said that informal logic, like applied ethics, has become a standard offering that helps sustain philosophy departments in North America by contributing to what Rescher describes as “The rapid growth of ‘applied philosophy’ ...[that] is a striking structural feature of contemporary North American philosophy.” (p. 9). The goal of applied philosophy is philosophically informed and nuanced reasoning that addresses complex real life situations. Informal logic is one field which has made a valuable contribution to this goal.

• Ajdukiewicz, K., 1974. Pragmatic Logic , O. Wojtasiewicz (trans.), Dordrecht/Boston/Warsaw: D. Reidel Publishing Company & PWN – Polish Scientific Publishers. (English translation of Logika pragmatyczna , originally published 1965.)
• Arnauld, Antoine, and Pierre Nicole, 1662. Logic, or, The Art of Thinking , Thomas Spencer Baynes (trans.), Edinburgh: Sutherland and Knox, 1850. [ Arnauld and Nicole 1662 [1850] available online ]
• Barwise, Jon and John Etchemendy, 1998. “Computers, Visualization, and the Nature of Reasoning,” in T. W. Bynum and James H. Moor (eds.), The Digital Phoenix: How Computers are Changing Philosophy , pp. 93–116, London: Blackwell.
• Battersby, Mark and Sharon Bailin, 2011. “Fallacy identification in a dialectical approach to teaching critical thinking” , OSSA Conference Archive , Windsor: University of Windsor.
• Battersby, Mark, 2016. Is That a Fact? A Field Guide for Evaluating Statistical and Scientific Information , Peterborough: Broadview Press.
• Bennett, Bo, 2018. Logically … Fallacious: The Ultimate Collection of over 300 Logical Fallacies , Sudbury, MA: ArchieBoy LLC.
• Bermejo Luque, Lilian, 2011. Giving Reasons: A Linguistic-Pragmatic Approach to Argumentation Theory , Dordrecht: Springer.
• Blair, J. Anthony (ed.), 2021. Studies in Critical Thinking Windsor: Windsor Studies in Argumentation (Volume 8).
• ––– and Christopher W. Tindale (eds.), 2020. Rigour and Reason: Essays in Honour of Hans Vilhelm Hansen Windsor: Windsor Studies in Argumentation (Volume 10).
• –––, 2015. “What Is Informal Logic?” Reflections on Theoretical Issues in Argumentation (Argumentation Library, Volume 28), Frans H. van Eemeren and Bart Garssen (eds.), Dordrecht: Springer.
• –––, 2012. Groundwork in the Theory of Argumentation: Selected Papers of J. Anthony Blair , Dordrecht: Springer.
• –––, 1996. “The Possibility and Actuality of Visual Arguments,” Argumentation and Advocacy , 33(1): 23–39.
• Blair, J. Anthony and Ralph H. Johnson, 1980. Informal logic: the first international symposium , Inverness, CA : Edgepress.
• Bowell, Tracy and Gary Kemp, 2014. Critical Thinking: A Concise Guide , 4th ed., Routledge: London.
• Brinton, Alan and Douglas Walton, 1997. Historical Foundations of Informal Logic , Aldershot: Ashgate Publishing.
• Budzynska, Katarzyna, Michal Araszkiewicz, Barbara Bogołȩbska, Piotr Cap, Tadeusz Ciecierski,Kamila Debowska-Kozlowska, Barbara Dunin-Kȩplicz, Marcin Dziubiński, Michał Federowicz, Anna Gomolińska, Andrzej Grabowski, Teresa Hołówka, Łukasz Jochemczyk, Magdalena Kacprzak,Paweł Kawalec, Maciej Kielar, Andrzej Kisielewicz, Marcin Koszowy, Robert Kublikowski, Piotr Kulicki, Anna Kuzio, Piotr Lewiński, Jakub Z. Lichański, Jacek Malinowski, Witold Marciszewski, Edward Nieznański, Janina Pietrzak, Jerzy Pogonowski, Tomasz A. Puczyłowski, Jolanta Rytel, Anna Sawicka, Marcin Selinger, Andrzej Skowron, Joanna Skulska, Marek Smolak, Małgorzata Sokół, Agnieszka Sowińska, Piotr Stalmaszczyk, Tomasz Stawecki, Jarosław Stepaniuk, Alina Strachocka, Wojciech Suchoń, Krzysztof Szymanek, Justyna Tomczyk, Robert Trypuz, Kazimierz Trzȩsicki, Mariusz Urbański, Ewa Wasilewska-Kamińska, Krzysztof A. Wieczorek, Maciej Witek, Urszula Wybraniec-Skardowska, · Olena Yaskorska, Maria Załȩska, Konrad Zdanowski, Tomasz Żurek, 2014. “The Polish School of Argumentation: A Manifesto,” Argumentation , 28(3): 267–282. .
• Browne, M. Neil and Stuart M. Keeley, 2018. Asking the Right Questions: A Guide to Critical Thinking , 12th ed., Englewood Cliffs: Prentice Hall.
• Burke, Michael B., 1994. “Denying the Antecedent: A Common Fallacy?” Informal Logic , 16(1): 23–30.
• Carney, James D. and Richard K. Scheer, 1964. Fundamentals of Logic , New York: Macmillan.
• Copi, Irving, 1953. Introduction to Logic , New York: Macmillan.
• Crosswhite, James, 1996. The Rhetoric of Reason: Writing and the Attractions of Argument , Madison: University of Wisconsin Press.
• –––, 2013. Deep Rhetoric: Philosophy, Reason, Violence, Justice, Wisdom , Chicago: University of Chicago Press.
• Dove, Ian, 2016. “Visual Scheming: Assessing Visual Arguments,” Argumentation and Advocacy (Special Issue: Twenty Years of Visual Argument), D. Godden, Catherine H. Palczewski, and Leo Groarke (eds.), 52(4): 254–264.
• Dumke, G., 1980. Chancellor’s Executive Order 338 , Chancellor’s Office, Long Beach: California State University.
• Eckstein, Justin 2018. “ Figuring Sound ” Informal Logic , 38(3): 341–345.
• Eemeren, Frans H. van, B. Garssen, E.C.W. Krabbe, F.A. Snoeck Henkemans, B. Verheij, and J.H.M. Wagemans, 2014, Handbook of Argumentation Theory , Dordrecht: Springer.
• Eemeren, Frans H. van (ed.), 2002. Advances In Pragma-Dialectics , Amsterdam: SicSat.
• Eemeren, Frans H. van and Rob Grootendorst, 1992. Argumentation, Communication, and Fallacies: A Pragma-Dialectical Perspective , Hillsdale, NJ: Lawrence Erlbaum Associates.
• Ennis, R.H., 2013. “Critical Thinking Across the Curriculum.” D. Mohammed & M. Lewiński (eds.), Virtues of Argumentation: Proceedings of the 10th International Conference of the Ontario Society for the Study of Argumentation (OSSA), Windsor, ON: OSSA, pp. 1–16, available online .
• –––, 2011. “Critical Thinking: Reflection and Perspective” (Part I), Inquiry , 26(1): 4–18.
• Feldman, Richard, 2009. “Thinking, Reasoning, and Education,” in Harvey Siegel (ed.), Oxford Handbook of Philosophy of Education , pp. 67–82, Oxford: Oxford University Press.
• Feteris, Eveline, Bart Garssen and Francisca Snoeck Henkemans, 2011. Keeping in Touch with Pragma-Dialectics , Amsterdam: John Benjamins.
• Finocchiaro, Maurice A., 1997. “ The Port-Royal Logic ’s Theory of Argument,” Argumentation , 11: 393–410.
• Fisher, Walter R. 1987. Human Communication as Narration. Toward a Philosophy of Reason, Value, and Action , Columbia: University of South Carolina Press.
• Fogelin, Robert J. 1978. Understanding Arguments: An Introduction to Informal Logic , New York: Harcourt, Brace, Jovanovich.
• Gilbert, Michael, 2014. Arguing with people , Peterborough: Broadview Press.
• –––, 2001. How to Win an Argument , New York: MJF Books.
• –––, 1997. Coalescent Argumentation , Mahwah, NJ: Lawrence Erlbaum Associates.
• Godden, David, Catherine H. Palczewski, Leo Groarke (eds.), 2016. Twenty Years of Visual Argument: Special Issue, Argumentation and Advocacy , Vol. 52, No. 4, Spring.
• Godden, David M., 2014. “Mill’s System of Logic” in The Oxford Handbook of British Philosophy in the Nineteenth Century , W.J. Mander (ed.), Oxford: Oxford University Press, pp. 44–70.
• –––, 2005. “Deductivism as an Interpretive Strategy: A Reply to Groarke’s Recent Defense of Reconstructive Deductivism,” Argumentation and Advocacy , 41(3): 168–83.
• Goldman, Alvin I., 1999. Knowledge in a Social World , Oxford: Clarendon Press.
• Goodwin, Jean and Viviana Cortes, 2010. “Theorists’ and practitioners’ spatial metaphors for argumentation: A corpus-based approach,” Verbum , 23: 163–78.
• Govier, Trudy, 2019. A Practical Study of Argument , Enhanced 7th ed., Boston: Wadsworth.
• –––, 1999. The Philosophy of Argument , Newport News: Vale Press.
• –––, 1987. Problems in Argument Analysis and Evaluation , Amsterdam: Mouton de Gruyter/Foris (reprinted as Volume 6 in Windsor Studies in Argumentation).
• Govier, T. & L. Ayers, 2012. “Logic, Parables, and Argument,” Informal Logic , 32(2): 161–189.
• Grennan, Wayne, 1997. Informal Logic: Issues and Techniques: A proposal for a new system of argument evaluation , Montreal: McGill-Queen’s University Press.
• Groarke, Leo A., Christopher W. Tindale, and Linda Carozza, 2021. Good Reasoning Matters! , 6th edition, Toronto: Oxford University Press.
• Groarke, Leo, 2020. “How to Define an Informal Logic,” in Blair and Tindale (eds.), Rigour and Reason , pp. 231–251.
• –––, 2019. “Matching Schemes of Argument: Verbal, Visual, Multimodal,” in Bart Garssen, David Godden, Gordon R. Mitchell, Jean H.M. Wagemans (eds.), Proceedings of the Ninth Conference of the International Society for the Study of Argumentation , Amsterdam: Sic Sat, pp. 443–457.
• –––, 2018. “ Auditory Arguments: The Logic of ‘Sound’ Arguments ”, Informal Logic , 38:3, 312–340.
• –––, 2015. “ Going Multimodal: What is a Mode of Arguing and Why Does it Matter? ”, Argumentation , 29(2): 133–155.
• –––, 1999. “Deductivism Within Pragma-Dialectics,” Argumentation , 13: 1–16.
• Hamblin, Charles Leonard, 1970. Fallacies , London: Methuen.
• Hansen, Hans V., 2012. “ Are there methods of informal logic? ” in F. Zenker (ed.), Argumentation: Community and Cognition, Proceedings of the 9th Conference of the Ontario Society for the Study of Argumentation , pp. 1–13, Windsor: Centre for Research on Reasoning, Argumentation, and Rhetoric.
• –––, 2002. “The Straw Thing of Fallacy Theory: The Standard Definition of ‘Fallacy’,” Argumentation , 16(2): 133–155.
• Hansen, Hans V. and Robert C. Pinto (eds.), 1995. Fallacies: Classical and Contemporary Readings , University Park, PA: Pennsylvania State University Press.
• Harman, Gilbert H., 1965. “The Inference to the Best Explanation,” The Philosophical Review , 74(1): 88–95.
• Harrison, Frank R. III, 1969. Deductive Logic and Descriptive Language , London: Prentice Hall.
• Hitchcock, David, 2007. “Informal logic and the concept of argument,” in Dale Jacquette (ed.), Philosophy of Logic (Volume 5, Handbook of the Philosophy of Science), Amsterdam: Elsevier, pp. 101–129.
• –––, 2002. “The Practice of Argumentative Discussion,” Argumentation , 16(3): 287–298.
• –––, 1995. “Do Fallacies Have a Place in the Teaching of Reasoning Skills or Critical Thinking?” in Hans V. Hansen and Robert C. Pinto (eds.), Fallacies: Classical and Contemporary Readings , pp. 319–327, University Park, PA: Pennsylvania State University Press.
• Hoffman, Michael H.G., 2016. “Reflective Argumentation: A Cognitive Function of Arguing,” Argumentation , 30: 1–33.
• Hughes, William, Jonathan Lavery and Katheryn Doran, 2014. Critical Thinking: An Introduction to the Basic Skills , 7th ed., Peterborough: Broadview.
• Johnson, Ralph H., 2011. “Informal Logic and Deductivism,” Studies in Logic , 4(1): 17–37.
• –––, 2007. “Making Sense of ‘Informal Logic’,” Informal Logic , 26(3): 231–58.
• –––, 2000. Manifest Rationality: A Pragmatic Theory of Argument , Mahwah, NJ: Lawrence Erlbaum Associates.
• –––, 1996 [2014]. The Rise of Informal Logic , Newport News, VA: Vale Press (1996); Digital edition , University of Windsor: Windsor Studies in Argumentation (Volume 2, 2014).
• Johnson, Ralph H. and J. Anthony Blair, 1997. “Informal Logic in the Twentieth Century,” in Douglas Walton and Alan Brinton (eds.), Historical Foundations of Informal Logic , pp. 158–177. Aldershot, England: Ashgate.
• –––, 1994. “Informal Logic: Past and Present,” in Ralph H. Johnson and J. Anthony Blair (eds.), New Essays in Informal Logic , pp. 1–19, Windsor: Informal Logic Enterprizes.
• –––, 1985. “Informal Logic: The Past Five Years 1978–1983,” American Philosophical Quarterly , 22(3): 181–196.
• –––, 1977 [1994]. Logical Self-Defense , 1st edition (1977), 3rd edition (1994), Toronto: McGraw Hill-Ryerson.
• Jørgensen, Charlotte, Christian Kock and Lone Rørbech, 1995. “Hostility in Public Debate,” in Frans H. van Eemeren, Rob Grootendorst, J. Anthony Blair and Charles Willard (eds.), Special Fields and Case Studies (Proceedings of the Third ISSA Conference on Argumentation, Vol. IV), pp. 365–73, Amsterdam: International Centre for the Study of Argumentation.
• –––, 1991. “Rhetoric That Shifts Votes: A Large-Scale Exploratory Study of Persuasion in Issue-Oriented Public Debates,” Political Communication , 15: 283–299.
• Kahane, Howard, 1971 [1995]. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life , 1st edition (1971), 7th edition (1995), Belmont: Wadsworth.
• Kahane, Howard and Nancy M. Cavender, 2002. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life , 9th Edition, Belmont: Wadsworth.
• Kišiček, Gabrijela 2018. “ Can we Translate Sounds into Words? ” Informal Logic , Vol. 38, No. 3(2018), pp. 346–361.
• –––, 2014. “The role of paralinguistic features in the analysis of multimodal argumentation,” in Proceedings of the 8th international conference on argumentation , University of Amsterdam: International Society for the Study of Argumentation (ISSA).
• Kjeldsen, Jens, 2015. “ The Study of Visual and Multimodal Argumentation, ” Argumentation , 29(2): 115–132.
• Koszowy, Marcin. 2010. “Pragmatic Logic and the Study of Argumentation,” Studies in Logic, Grammar and Rhetoric , 22(35): 29–44.
• Lazere, Donald, 1987. “Critical Thinking in College English Studies,” ERIC Digest (ED284275), Urbana, IL: ERIC Clearinghouse on Reading and Communication Skills.
• Little, J. Frederick, 1980. Critical Thinking and Decision Making: A Methodology of Analysis, Evaluation and Review , Toronto: Butterworths.
• Lunsford, Andrea, John J. Ruszkiewicz, and Keith Walters, 2012. Everything’s an Argument , 6th Edition, Boston: Bedford/St. Martin.
• Mans, Dieter and Gerhard Preyer (eds.), 1999. Reasoning and Argumentation , Special Issue, Protosociology , 13.
• Mill, John Stuart, 1882. A System of Logic, Rationinative and Inductive, Being a Connected View of the Principles of Evidence, and the Methods of Scientific Investigation , 8th edition, New York: Harper & Brothers.
• Mercier, Hugo and Dan Sperber, 2011. “Why do humans reason? Arguments for an argumentative theory,” Behavioral and Brain Sciences , 34: 57–111.
• Mochales, Raquel and Aagje Ieven, 2009. “Creating an Argumentation Corpus: Do Theories Apply to Real Arguments? A Case Study on the Legal Argumentation,” Proceedings of the 12th International Conference on Artificial Intelligence and Law , New York: Association for Computing Machinery.
• Munson, Ronald, 1976. The Way of Words: An Informal Logic , Boston: Houghton Mifflin.
• Nussbaum, Martha C., 1990. Love’s Knowledge: Essays on Philosophy and Literature , Oxford: Oxford University Press.
• Olmos, Paula, 2014. “Classical Fables as Arguments: Narration and Analogy,” in Henrique Jales Ribeiro (ed.), Systematic Approaches to Argument by Analogy (Argumentation Library, Volume 25), pp. 189–208, Dordrecht: Springer.
• Plumer, Gilbert, 2015. “On Novels as Arguments,” Informal Logic , 35: 488–507.
• Paul, Richard and Linda Elder, 2012. Fallacies: The Art of Mental Trickery , Tomales, CA: Foundation for Critical Thinking.
• Pinto, Robert C., 2001. Argument, Inference and Dialectic: Collected Papers on Informal Logic , Dordrecht: Kluwer.
• Pospesel, Howard, 2002. Introduction to Logic: Predicate Logic , 2nd edition, Saddle River: Pearson Education.
• Pospesel, Howard and David Marans, 1978. Arguments: Deductive Logic Exercises , Saddle River: Pearson Education.
• Prakken, H. 2010a. “An abstract framework for argumentation with structured arguments,” Argument and Computation , 1: 93–124.
• –––, 2010b. “On the nature of argument schemes,” in C.A. Reed & C. Tindale (eds.) Dialectics, Dialogue and Argumentation. An Examination of Douglas Walton’s Theories of Reasoning and Argument , pp. pp 167–185. London: College Publications.
• Puppo, Federico (ed.), 2019. Informal Logic: A ‘Canadian’ Approach to Argument , Windsor: Windsor Studies in Argumentation, Vol. 9.
• Rahwana, Iyad, Fouad Zablitha, and Chris Reed, 2007. “Laying the foundations for a World Wide Argument Web,” Artificial Intelligence , 171 (July-October): 897–921.
• Reed, C.A. and T.J. Norman, 2004. Argumentation Machines: New Frontiers in Argument and Computation , Dordrecht: Kluwer Academic Publishers.
• Reed, C.A. and D.N. Walton, 2002. “ Applications of Argumentation Schemes ” in Hansen, H.V., C. W. Tindale, J.A. Blair, and R.H. Johnson (eds.), Argumentation and Its Applications: Proceedings of the 4th Conference of the Ontario Society for the Study of Argument , pp. 1–12, Windsor: Ontario Society for the Study of Argumentation.
• Rescher, Nicholas, 2005. Studies in Twentieth Century Philosophy , Frankfurt: Ontos.
• Rodes, Robert E. and Howard Pospesel, 1991. Premises and Conclusions: Symbolic Logic for Legal Analysis , Notre Dame: University of Notre Dame Press.
• Ryle, Gilbert, 1954. Dilemmas: The Tarner Lectures , Cambridge: Cambridge University Press.
• Seay, Gary and Susana Nuccetelli, 2012. How to Think Logically , 2nd. ed., Boston: Pearson.
• Siegel, Harvey, 1988. Educating reason: rationality, critical thinking, and education , New York: Routledge.
• Shelley, Cameron, 2003. “Aspects of visual argument: A study of the ‘March of Progress’,” Informal Logic , 21(2): 92–112.
• Sobocan, Jan (ed.), 2021. Critical Thinking, Education and Assessment: Can Critical Thinking Be Tested? , 2nd ed. Windsor: Windsor Studies in Argument.
• Thagard, Paul, 2011. “ Critical Thinking and Informal Logic: Neuropsychological Perspectives, ” Informal Logic , 31(3): 152–70.
• Tindale, Christopher W., 2021. The Anthropology of Argument: Cultural Foundations of Rhetoric and Reason , New York: Routledge.
• –––, 2010. Reason’s Dark Champions: Constructive Strategies of Sophistic Argument , Columbia: South Carolina Press.
• –––, 2004. Rhetorical Argumentation: Principles of Theory and Practice , Ithaca, NY: Sage Publications.
• –––, 1999. Acts of Arguing: A Rhetorical Model of Argument , Albany, NY: State University of New York Press.
• Toulmin, Stephen, 1958 [2003]. The Uses of Argument , Cambridge: Cambridge University Press; revised edition, 2003.
• Tseronis, Assimakis and Charles Forceville, eds. 2017. Multimodal Argumentation and Rhetoric in Media Genres, (Argumentation in Context, Volume 14), Amsterdam: John Benjamins.
• Verheij, Bart, 2014. “Argumentation and Artificial Intelligence,” Chapter 11 in Eemeren et al., 2014.
• –––, 1999. “Automated Argument Assistance for Lawyers,” Proceedings of the Seventh International Conference on Artificial Intelligence and Law , New York: Association of Computing Machinery, pp. 43–52.
• Walton, Douglas N., 2012. “Story similarity in arguments from analogy,” Informal Logic , 32: 190–221.
• –––, 2007. Dialog Theory for Critical Argumentation , Amsterdam: John Benjamins Publishing Company.
• –––, 2004. Abductive Reasoning , Tuscaloosa, University of Alabama Press.
• –––, 2000. Scare Tactics: Arguments that Appeal to Fear and Threats (Argumentation Library: Volume 3), Berlin: Springer.
• –––, 1989. Informal Logic: A Handbook for Critical Argumentation , New York: Cambridge University Press.
• Walton, Douglas, Christopher Reed, Fabrizio Macagno, 2008. Argumentation Schemes , Cambridge: Cambridge University Press.
• Weston, Anthony, 2018. A Rulebook for Arguments , 5th ed., Indianapolis: Hackett.
• Whately, Richard, 1826. Elements of logic , London: B. Fellowes.
• –––, 1830. Elements of rhetoric , 3rd edition, Oxford: W. Baxter.
• Wigmore, John Henry, 1913. The principles of judicial proof: as given by logic, psychology, and general experience, and illustrated in judicial trials , Boston: Little Brown.
• Wilson, David Carl, 2020. A Guide to Good Reasoning: Cultivating Intellectual Virtues , 2nd edition, Twin Cities: University of Minesota Libraries.
• Woods, John and Douglas Walton 1982. Argument: The Logic of the Fallacies , Roronto: McGraw-Hill Ryerson.
• Woods, John, 2000. “How Philosophical is Informal Logic? ” Informal Logic , 20(2): 139–167.
• –––, 1995. “Appeal to Force,” in Hansen and Pinto 1995, pp. 240–250.
• Zenker, F. 2013. Bayesian Argumentation: The practical side of probability (Synthese Library 362), Dordrecht: Springer.

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• Fallacies , entry by Bradley Dowden in the Internet Encyclopedia of Philosophy , J. Fieser (ed.)
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abduction | Aristotle, General Topics: rhetoric | children, philosophy for | fallacies | feminist philosophy, topics: perspectives on argumentation | logic: and games | logic: classical | logic: inductive | logical consequence | Port Royal Logic | science: and pseudo-science

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The ability to think critically calls for a higher-order thinking than simply the ability to recall information.

Definitions of critical thinking, its elements, and its associated activities fill the educational literature of the past forty years. Critical thinking has been described as an ability to question; to acknowledge and test previously held assumptions; to recognize ambiguity; to examine, interpret, evaluate, reason, and reflect; to make informed judgments and decisions; and to clarify, articulate, and justify positions (Hullfish & Smith, 1961; Ennis, 1962; Ruggiero, 1975; Scriven, 1976; Hallet, 1984; Kitchener, 1986; Pascarella & Terenzini, 1991; Mines et al., 1990; Halpern, 1996; Paul & Elder, 2001; Petress, 2004; Holyoak & Morrison, 2005; among others).

After a careful review of the mountainous body of literature defining critical thinking and its elements, UofL has chosen to adopt the language of Michael Scriven and Richard Paul (2003) as a comprehensive, concise operating definition:

Critical thinking is the intellectually disciplined process of actively and skillfully conceptualizing, applying, analyzing, synthesizing, and/or evaluating information gathered from, or generated by, observation, experience, reflection, reasoning, or communication, as a guide to belief and action.

Paul and Scriven go on to suggest that critical thinking is based on: "universal intellectual values that transcend subject matter divisions: clarity, accuracy, precision, consistency, relevance, sound evidence, good reasons, depth, breadth, and fairness. It entails the examination of those structures or elements of thought implicit in all reasoning: purpose, problem, or question-at-issue, assumptions, concepts, empirical grounding; reasoning leading to conclusions, implication and consequences, objections from alternative viewpoints, and frame of reference. Critical thinking - in being responsive to variable subject matter, issues, and purposes - is incorporated in a family of interwoven modes of thinking, among them: scientific thinking, mathematical thinking, historical thinking, anthropological thinking, economic thinking, moral thinking, and philosophical thinking."

This conceptualization of critical thinking has been refined and developed further by Richard Paul and Linder Elder into the Paul-Elder framework of critical thinking. Currently, this approach is one of the most widely published and cited frameworks in the critical thinking literature. According to the Paul-Elder framework, critical thinking is the:

• Analysis of thinking by focusing on the parts or structures of thinking ("the Elements of Thought")
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The University of Louisville chose the Paul-Elder model of Critical Thinking as the approach to guide our efforts in developing and enhancing our critical thinking curriculum. The Paul-Elder framework was selected based on criteria adapted from the characteristics of a good model of critical thinking developed at Surry Community College. The Paul-Elder critical thinking framework is comprehensive, uses discipline-neutral terminology, is applicable to all disciplines, defines specific cognitive skills including metacognition, and offers high quality resources.

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The use of a single critical thinking framework is an important aspect of institution-wide critical thinking initiatives (Paul and Nosich, 1993; Paul, 2004). According to this view, critical thinking instruction should not be relegated to one or two disciplines or departments with discipline specific language and conceptualizations. Rather, critical thinking instruction should be explicitly infused in all courses so that critical thinking skills can be developed and reinforced in student learning across the curriculum. The use of a common approach with a common language allows for a central organizer and for the development of critical thinking skill sets in all courses.

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