logic and critical thinking fallacies

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Critical Thinking and Decision-Making  - Logical Fallacies

Critical thinking and decision-making  -, logical fallacies, critical thinking and decision-making logical fallacies.

Critical Thinking and Decision-Making: Logical Fallacies

Lesson 7: logical fallacies.

/en/problem-solving-and-decision-making/how-critical-thinking-can-change-the-game/content/

Logical fallacies

If you think about it, vegetables are bad for you. I mean, after all, the dinosaurs ate plants, and look at what happened to them...

Let's pause for a moment: That argument was pretty ridiculous. And that's because it contained a logical fallacy .

A logical fallacy is any kind of error in reasoning that renders an argument invalid . They can involve distorting or manipulating facts, drawing false conclusions, or distracting you from the issue at hand. In theory, it seems like they'd be pretty easy to spot, but this isn't always the case.

Watch the video below to learn more about logical fallacies.

Sometimes logical fallacies are intentionally used to try and win a debate. In these cases, they're often presented by the speaker with a certain level of confidence . And in doing so, they're more persuasive : If they sound like they know what they're talking about, we're more likely to believe them, even if their stance doesn't make complete logical sense.

False cause

One common logical fallacy is the false cause . This is when someone incorrectly identifies the cause of something. In my argument above, I stated that dinosaurs became extinct because they ate vegetables. While these two things did happen, a diet of vegetables was not the cause of their extinction.

Maybe you've heard false cause more commonly represented by the phrase "correlation does not equal causation ", meaning that just because two things occurred around the same time, it doesn't necessarily mean that one caused the other.

A straw man is when someone takes an argument and misrepresents it so that it's easier to attack . For example, let's say Callie is advocating that sporks should be the new standard for silverware because they're more efficient. Madeline responds that she's shocked Callie would want to outlaw spoons and forks, and put millions out of work at the fork and spoon factories.

A straw man is frequently used in politics in an effort to discredit another politician's views on a particular issue.

Begging the question

Begging the question is a type of circular argument where someone includes the conclusion as a part of their reasoning. For example, George says, “Ghosts exist because I saw a ghost in my closet!"

George concluded that “ghosts exist”. His premise also assumed that ghosts exist. Rather than assuming that ghosts exist from the outset, George should have used evidence and reasoning to try and prove that they exist.

Since George assumed that ghosts exist, he was less likely to see other explanations for what he saw. Maybe the ghost was nothing more than a mop!

False dilemma

The false dilemma (or false dichotomy) is a logical fallacy where a situation is presented as being an either/or option when, in reality, there are more possible options available than just the chosen two. Here's an example: Rebecca rings the doorbell but Ethan doesn't answer. She then thinks, "Oh, Ethan must not be home."

Rebecca posits that either Ethan answers the door or he isn't home. In reality, he could be sleeping, doing some work in the backyard, or taking a shower.

Most logical fallacies can be spotted by thinking critically . Make sure to ask questions: Is logic at work here or is it simply rhetoric? Does their "proof" actually lead to the conclusion they're proposing? By applying critical thinking, you'll be able to detect logical fallacies in the world around you and prevent yourself from using them as well.

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• Knowledge Base
• Logical Fallacies | Definition, Types, List & Examples

Logical Fallacies | Definition, Types, List & Examples

Published on April 20, 2023 by Kassiani Nikolopoulou . Revised on October 9, 2023.

A logical fallacy is an argument that may sound convincing or true but is actually flawed. Logical fallacies are leaps of logic that lead us to an unsupported conclusion. People may commit a logical fallacy unintentionally, due to poor reasoning, or intentionally, in order to manipulate others.

Because logical fallacies can be deceptive, it is important to be able to spot them in your own argumentation and that of others.

Table of contents

Logical fallacy list (free download), what is a logical fallacy, types of logical fallacies, what are common logical fallacies, logical fallacy examples, other interesting articles, frequently asked questions about logical fallacies.

There are many logical fallacies. You can download an overview of the most common logical fallacies by clicking the blue button.

Logical fallacy list (Google Docs)

A logical fallacy is an error in reasoning that occurs when invalid arguments or irrelevant points are introduced without any evidence to support them. People often resort to logical fallacies when their goal is to persuade others. Because fallacies appear to be correct even though they are not, people can be tricked into accepting them.

The majority of logical fallacies involve arguments—in other words, one or more statements (called the premise ) and a conclusion . The premise is offered in support of the claim being made, which is the conclusion.

There are two types of mistakes that can occur in arguments:

• A factual error in the premises . Here, the mistake is not one of logic. A premise can be proven or disproven with facts. For example, If you counted 13 people in the room when there were 14, then you made a factual mistake.
• The premises fail to logically support the conclusion . A logical fallacy is usually a mistake of this type. In the example above, the students never proved that English 101 was itself a useless course—they merely “begged the question” and moved on to the next part of their argument, skipping the most important part.

In other words, a logical fallacy violates the principles of critical thinking because the premises do not sufficiently support the conclusion, while a factual error involves being wrong about the facts.

There are several ways to label and classify fallacies, such as according to the psychological reasons that lead people to use them or according to similarity in their form. Broadly speaking, there are two main types of logical fallacy, depending on what kind of reasoning error the argument contains:

Informal logical fallacies

Formal logical fallacies.

An informal logical fallacy occurs when there is an error in the content of an argument (i.e., it is based on irrelevant or false premises).

Informal fallacies can be further subdivided into groups according to similarity, such as relevance (informal fallacies that raise an irrelevant point) or ambiguity (informal fallacies that use ambiguous words or phrases, the meanings of which change in the course of discussion).

“ Some philosophers argue that all acts are selfish . Even if you strive to serve others, you are still acting selfishly because your act is just to satisfy your desire to serve others.”

A formal logical fallacy occurs when there is an error in the logical structure of an argument.

Premise 2: The citizens of New York know that Spider-Man saved their city.

Conclusion: The citizens of New York know that Peter Parker saved their city.  

This argument is invalid, because even though Spider-Man is in fact Peter Parker, the citizens of New York don’t necessarily know Spider-Man’s true identity and therefore don’t necessarily know that Peter Parker saved their city.

A logical fallacy may arise in any form of communication, ranging from debates to writing, but it may also crop up in our own internal reasoning. Here are some examples of common fallacies that you may encounter in the media, in essays, and in everyday discussions.

Red herring logical fallacy

The red herring fallacy is the deliberate attempt to mislead and distract an audience by bringing up an unrelated issue to falsely oppose the issue at hand. Essentially, it is an attempt to change the subject and divert attention elsewhere.

Bandwagon logical fallacy

The bandwagon logical fallacy (or ad populum fallacy ) occurs when we base the validity of our argument on how many people believe or do the same thing as we do. In other words, we claim that something must be true simply because it is popular.

This fallacy can easily go unnoticed in everyday conversations because the argument may sound reasonable at first. However, it doesn’t factor in whether or not “everyone” who claims x is in fact qualified to do so.

Straw man logical fallacy

The straw man logical fallacy is the distortion of an opponent’s argument to make it easier to refute. By exaggerating or simplifying someone’s position, one can easily attack a weak version of it and ignore their real argument.

Person 2: “So you are fine with children taking ecstasy and LSD?”

Slippery slope logical fallacy

The slippery slope logical fallacy occurs when someone asserts that a relatively small step or initial action will lead to a chain of events resulting in a drastic change or undesirable outcome. However, no evidence is offered to prove that this chain reaction will indeed happen.

Hasty generalization logical fallacy

The hasty generalization fallacy (or jumping to conclusions ) occurs when we use a small sample or exceptional cases to draw a conclusion or generalize a rule.

A false dilemma (or either/or fallacy ) is a common persuasion technique in advertising. It presents us with only two possible options without considering the broad range of possible alternatives.

In other words, the campaign suggests that animal testing and child mortality are the only two options available. One has to save either animal lives or children’s lives.

People often confuse correlation (i.e., the fact that two things happen one after the other or at the same time) with causation (the fact that one thing causes the other to happen).

It’s possible, for example, that people with MS have lower vitamin D levels because of their decreased mobility and sun exposure, rather than the other way around.

It’s important to carefully account for other factors that may be involved in any observed relationship. The fact that two events or variables are associated in some way does not necessarily imply that there is a cause-and-effect relationship between them and cannot tell us the direction of any cause-and-effect relationship that does exist.

If you want to know more about fallacies , research bias , or AI tools , make sure to check out some of our other articles with explanations and examples.

• ChatGPT vs human editor
• ChatGPT citations
• Is ChatGPT trustworthy?
• Using ChatGPT for your studies
• Sunk cost fallacy
• Straw man fallacy
• Slippery slope fallacy
• Either or fallacy
• Appeal to emotion fallacy
• Non sequitur fallacy

Research bias

• Implicit bias
• Framing bias
• Cognitive bias
• Optimism bias
• Hawthorne effect
• Affect heuristic

An ad hominem (Latin for “to the person”) is a type of informal logical fallacy . Instead of arguing against a person’s position, an ad hominem argument attacks the person’s character or actions in an effort to discredit them.

This rhetorical strategy is fallacious because a person’s character, motive, education, or other personal trait is logically irrelevant to whether their argument is true or false.

Name-calling is common in ad hominem fallacy (e.g., “environmental activists are ineffective because they’re all lazy tree-huggers”).

An appeal to ignorance (ignorance here meaning lack of evidence) is a type of informal logical fallacy .

It asserts that something must be true because it hasn’t been proven false—or that something must be false because it has not yet been proven true.

For example, “unicorns exist because there is no evidence that they don’t.” The appeal to ignorance is also called the burden of proof fallacy .

People sometimes confuse cognitive bias and logical fallacies because they both relate to flawed thinking. However, they are not the same:

• Cognitive bias is the tendency to make decisions or take action in an illogical way because of our values, memory, socialization, and other personal attributes. In other words, it refers to a fixed pattern of thinking rooted in the way our brain works.
• Logical fallacies relate to how we make claims and construct our arguments in the moment. They are statements that sound convincing at first but can be disproven through logical reasoning.

In other words, cognitive bias refers to an ongoing predisposition, while logical fallacy refers to mistakes of reasoning that occur in the moment.

Sources in this article

We strongly encourage students to use sources in their work. You can cite our article (APA Style) or take a deep dive into the articles below.

Nikolopoulou, K. (2023, October 09). Logical Fallacies | Definition, Types, List & Examples. Scribbr. Retrieved April 15, 2024, from https://www.scribbr.com/fallacies/logical-fallacy/

Jin, Z., Lalwani, A., Vaidhya, T., Shen, X., Ding, Y., Lyu, Z., Sachan, M., Mihalcea, R., & Schölkopf, B. (2022). Logical Fallacy Detection. arXiv (Cornell University) . https://doi.org/10.48550/arxiv.2202.13758

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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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Effectiviology

Logical Fallacies: What They Are and How to Counter Them

• A logical fallacy is a pattern of reasoning that contains a flaw, either in its logical structure or in its premises.

An example of a logical fallacy is the false dilemma , which is a logical fallacy that occurs when a limited number of options are incorrectly presented as being mutually exclusive to one another or as being the only options that exist, in a situation where that isn’t the case. For instance, a false dilemma occurs in a situation where someone says that we must choose between options A or B, without mentioning that option C also exists.

Fallacies, in their various forms, play a significant role in how people think and in how they communicate with each other, so it’s important to understand them. As such, the following article serves as an introductory guide to logical fallacies, which will help you understand what logical fallacies are, what types of them exist, and what you can do in order to counter them successfully.

Examples of logical fallacies

One example of a logical fallacy is the ad hominem fallacy , which is a fallacy that occurs when someone attacks the source of an argument directly, without addressing the argument itself. For instance, if a person brings up a valid criticism of the company that they work in, someone using the ad hominem fallacy might reply by simply telling them that if they don’t like the way things are done, then that’s their problem and they should leave.

Another example of a logical fallacy is the loaded question fallacy , which occurs when someone asks a question in a way that presupposes an unverified assumption that the person being questioned is likely to disagree with. An example of a loaded question is the following:

“Can you get this task done for me, or are you too busy slacking off?”

This question is fallacious, because it has a flawed premise, and specifically because it suggests that if the person being questioned says that they can’t get the task done, then that must be because they’re too busy slacking off.

Finally, another example of a logical fallacy is the argument from incredulity , which occurs when someone concludes that since they can’t believe that a certain concept is true, then it must be false, and vice versa. For instance, this fallacy is demonstrated in the following saying:

“I just can’t believe that these statistics are true, so that means they must be false.”

In this case, the speaker’s reasoning is fallacious, because their premises are flawed, and specifically their assumption that if they can’t believe the statistics that they’re shown are true, then that must mean that the statistics are false.

Formal and informal logical fallacies

There are two main types of logical fallacies:

• Formal fallacies. A formal logical fallacy occurs when there is a flaw in the logical structure of an argument, which renders the argument invalid and consequently also unsound . For example, a formal fallacy can occur because the conclusion of the argument isn’t based on its premises.
• Informal fallacies. An informal logical fallacy occurs when there is a flaw in the premises of an argument, which renders the argument  unsound , even though it may still be valid . For example, an informal fallacy can occur because the premises of an argument are false , or because they’re unrelated to the discussion at hand.

Therefore, there are two main differences between formal and informal logical fallacies. First, formal fallacies contain a flaw in their logical structure , while informal fallacies contain a flaw in their premises . Second, formal fallacies are invalid patterns of reasoning (and are consequently also unsound), while informal fallacies are unsound patterns of reasoning, but can still be valid.

For instance, the following is an example of a formal fallacy :

Premise 1: If it’s raining, then the sky will be cloudy. Premise 2: The sky is cloudy. Conclusion:  It’s raining.

Though both the premises in this example are true, the argument is invalid , since there is a flaw in its logical structure.

Specifically, premise 1 tells us that if it’s raining, then the sky will be cloudy, but that doesn’t mean that if the sky is cloudy (which we know it is, based on premise 2), then it’s necessarily raining. That is, it’s possible for the sky to be cloudy, without it raining, which is why we can’t reach the conclusion that is specified in the argument, and which is why this argument is invalid, despite the fact that its premises are true.

On the other hand, the following is an example of an informal fallacy :

Premise 1: The weatherman said that it’s going to rain next week. Premise 2: The weatherman is always right. Conclusion:  It’s going to rain next week.

Here, the logical structure of the argument is valid. Specifically, since premise 1 tells us that the weatherman said that it’s going to rain next week, and premise 2 tells us that the weatherman is always right, then based on what we know (i.e. on these premises), we can logically conclude that it’s going to rain next week.

However, there is a problem with this line of reasoning, since our assumption that the weatherman is always right (premise 2) is false . As such, even though the logical structure of the argument is valid, the use of a flawed premise means that the overall argument is unsound .

Overall, a sound argument is one that has a valid logical structure and true premises. A formal logical fallacy means that the argument is invalid, due to a flaw in its logical structure, which also means that it’s unsound. An informal logical fallacy means that the argument is unsound, due to a flaw in its premises, even though it has a valid logical structure.

Example of a formal logical fallacy

As we saw above, a formal fallacy occurs when there is an issue with the logical structure of an argument, which renders the argument invalid.

An example of a formal logical fallacy is the masked-man fallacy , which is committed when someone assumes that if two or more names or descriptions refer to the same thing, then they can be freely substituted with one another, in a situation where that’s not the case. For example:

Premise 1: The citizens of Metropolis know that Superman saved their city. Premise 2: Clark Kent is Superman. Conclusion: The citizens of Metropolis know that Clark Kent saved their city.

This argument is invalid, because even though Superman is in fact Clark Kent, the citizens of Metropolis don’t necessarily know Superman’s true identity, and therefore don’t necessarily know that Clark Kent saved their city. As such, even though both the premises of the argument are true, there is a flaw in the argument’s logical structure, which renders it invalid.

Example of an informal logical fallacy

As we saw above, an informal fallacy occurs when there is a flaw in the premises of an argument, which renders the argument unsound.

An example of an informal logical fallacy is the  strawman fallacy , which occurs when a person distorts their opponent’s argument, in order to make it easier to attack. For example:

Alex: I think we should increase the education budget. Bob: I disagree, because if we spend the entire budget on education, there won’t be any money left for other essential things.

Here, Bob’s argument is valid from a formal, logical perspective: if we spend the entire budget on education, there won’t be anything left to spend on other things.

However, Bob’s reasoning is nevertheless fallacious, because his argument contains a false, implicit premise, and namely the assumption that when Alex suggests that we should increase the education budget, he means that the entire budget should be allocated to education. As such, Bob’s argument is unsound, because it relies on flawed premises, and counters an irrelevant point that his opponent wasn’t trying to make.

Fallacious techniques that aren’t logical fallacies

The term ‘fallacious’ has two primary meanings:

• Containing a logical fallacy.
• Tending to deceive or mislead.

Accordingly, some misleading rhetorical techniques and patterns of reasoning can be described as “fallacious”, even if they don’t contain a logical fallacy.

For example, the Gish gallop is a fallacious debate technique, which involves attempting to overwhelm your opponent by bringing up as many arguments as possible, with no regard for the relevance, validity, or accuracy of those arguments. Though a Gish gallop may have some arguments that contain logical fallacies, it isn’t a single argument by itself, and therefore isn’t considered a logical fallacy. However, because its overall argumentation pattern revolves around the intent to deceive, this technique is said to be fallacious.

In this regard, note that logical fallacies, in general, tend to include a form of reasoning that is not only logically invalid or unsound in some way, but that is also misleading.

However, it’s important to keep in mind that fallacies and other fallacious techniques aren’t always used with the intention of misleading others. Rather, people often use fallacious arguments unintentionally, both when they’re talking to other people, as well as when they conduct their own internal reasoning process, because the fact that such arguments are misleading can lead those who use them to not notice that they’re flawed in the first place.

Logical fallacies are different from factual errors

It’s important to note that logical fallacies are errors in reasoning, rather than simple factual errors.

For example, though the statement “humans are birds” is flawed, that’s because it contains a simple factual error, rather than a logical fallacy. Conversely, the argument “humans have eyes, and birds also have eyes, therefore humans are birds” contains a logical fallacy, since there is a flaw in its logical structure, which renders it invalid.

How to counter logical fallacies

To counter the use of a logical fallacy, you should first identify the flaw in reasoning that it contains, and then point it out and explain why it’s a problem, or provide a strong opposing argument that counters it implicitly.

For example, consider a situation where someone uses the appeal to nature , which is an informal logical fallacy that involving claiming that something is either good because it’s considered ‘natural’, or bad because it’s considered ‘unnatural’.

Once you’ve identified the use of the fallacy, you can counter it by explaining why its premises are flawed. To achieve this, you can provide examples that demonstrate that things that are “natural” can be bad and that things that are “unnatural” can be good, or you can provide examples that demonstrate the issues with trying to define what “natural” and “unnatural” mean in the first place.

The steps in this approach, where you first identify the use of the fallacy and then either explain why it’s a problem or provide strong counterarguments, are generally the main ones to follow regardless of which fallacy is being used. However, there is some variability in terms of how you implement these steps when it comes to different fallacies and different circumstances, and an approach that will work well in one situation may fail in another.

For example, while a certain approach might work well when it comes to resolving a formal fallacy that you’ve used unintentionally in your own reasoning process, the same approach might be ineffective when it comes to countering an informal fallacy that was used intentionally by someone else for rhetorical purposes.

Finally, it’s also important to keep in mind that sometimes, when responding to the use of fallacious reasoning, dismantling the logic behind your opponent’s reasoning and highlighting its flaws might not work. This is because, in practice, human interactions and debates are highly complex, and involve more than just exchanging logically sound arguments with one another.

Accordingly, you should accept the fact that in some cases, the best way to respond to a logical fallacy in practice isn’t necessarily to properly address it from a logical perspective. For example, your best option might be to modify your original argument in order to counter the fallacious reasoning without explicitly addressing the fact that it’s fallacious, or your best option might be to refuse to engage with the fallacious argument entirely.

Account for unintentional use of fallacies

When you counter fallacies that other people use, it’s important to remember that not every use of a logical fallacy is intentional, and to act accordingly, since accounting for this fact can help you formulate a more effective response.

A useful concept to keep in mind in this regard is  Hanlon’s razor , which is a philosophical principle that suggests that when someone does something that leads to a negative outcome, you should avoid assuming that they acted out of an intentional desire to cause harm, as long as there is a different plausible explanation for their behavior. In this context, Hanlon’s razor means that, if you notice that someone is using a logical fallacy, you should avoid assuming that they’re doing so intentionally, as long as it’s reasonable to do so.

In addition, it’s important to remember that you too might be using logical fallacies unintentionally in your thinking and in your communication with others. To identify cases where you are doing this, try to examine your reasoning, and see if you can identify any flaws, either in the way that your arguments are structured, or in the premises that you rely on in order to make those arguments. Then, adjust your reasoning accordingly, in order to fix these flaws.

Make sure arguments are fallacious before countering

Before you counter an argument that you think is fallacious, you should make sure that it is indeed fallacious, to the best of your ability.

There are various ways to do this, including slowing down your own reasoning process so you can properly think through the argument, or asking the person who proposed the argument to clarify their position.

The approach of asking the other person to clarify their position is highly beneficial in general, because it helps demonstrate that you’re truly interested in what the other person has to say. Furthermore, in cases where the argument in question does turn out to be fallacious, this approach can often help expose the issues with it, and can also help the other person internalize these issues, in a way that you won’t always be able to achieve by pointing them out yourself.

Finally, note that a useful tool to remember in this regard is the principle of charity , which is a philosophical principle that denotes that, when interpreting someone’s statement, you should assume that the best possible interpretation of that statement is the one that the speaker meant to convey. In this context, the principle of charity means that you should not attribute falsehoods, logical fallacies, or irrationality to people’s argument, when there is a plausible, rational alternative available.

Remember fallacious arguments can have true conclusions

It’s important to keep in mind that even if an argument is fallacious, it can still have a true conclusion. Assuming that just because an argument is fallacious then its conclusion must necessarily be false is a logical fallacy in itself, which is known as the fallacy fallacy .

For instance, consider the following example of a formal logical fallacy (which we saw earlier, and which is known as affirming the consequent ):

Premise 1: If it’s raining, then the sky will be cloudy. Premise 2: The sky is cloudy. Conclusion: It’s raining.

This argument is logically invalid, since we can’t be sure that its conclusion is true based on the premises that we have (because it’s possible that the sky is cloudy but that it’s not raining at the same time). However, even though the argument itself is flawed, that doesn’t mean that its conclusion is necessarily false. Rather, it’s possible that the conclusion is true and that it is currently raining; we just can’t conclude this based on the premises

The same holds for informal fallacies. For example, consider the following argument:

Alex: It’s amazing how accurate this personality test I took is. Bob: No it isn’t, it’s pure nonsense.

Here, Bob is using an appeal to the stone , which is a logical fallacy that occurs when a person dismisses their opponent’s argument as absurd, without actually addressing it, or without providing sufficient evidence in order to prove its absurdity. However, even though Bob’s argument is fallacious, that doesn’t mean that its conclusion is wrong; it’s possible that the personality test in question is indeed nonsense, we just can’t tell whether that’s the case based on this argument alone.

Overall, the important thing to understand is that an argument can be fallacious and still have a conclusion that is factually correct. To assume otherwise is fallacious, which is why you shouldn’t discount people’s conclusions simply because the argument that they used to reach those conclusions contains a logical fallacy.

The difference between logical fallacies and cognitive biases

While logical fallacies and cognitive biases appear to be similar to each other, they are two different phenomena. Specifically, while logical fallacies are flawed patterns of argumentation , and are therefore a philosophical concept, cognitive biases are systematic errors in cognition , and are therefore a psychological concept.

Cognitive biases often occur at a more basic level of thinking, particularly when they’re rooted in people’s intuition, and they can lead to the use of various logical fallacies.

For example, the appeal to novelty is a logical fallacy that occurs when something is assumed to be either good or better than something else, simply because it’s perceived as being new and novel.

In some cases, people might use this fallacy due to a cognitive bias that causes them to instinctively prefer things that they perceive as newer. However, people can experience this instinctive preference for newer things without it leading to the use of the appeal to novelty, in cases where they recognize this preference and account for it properly. Furthermore, people can use arguments that rely on the appeal to novelty even if they don’t experience this instinctive preference, and even if they don’t truly believe in what they’re saying.

Overall, the main difference between logical fallacies and cognitive biases is that logical fallacies are a philosophical concept, that has to do with argumentation , while cognitive biases are a psychological concept, that has to do with cognition . In some cases, there is an association between cognitive biases and certain logical fallacies, but there are many situations where one appears entirely without the other.

Summary and conclusions

• To counter the use of a logical fallacy, you should first identify the flaw in reasoning that it involves, and then point it out and explain why it’s a problem, or provide a strong opposing argument that counters it implicitly.
• Note that there is some variability in terms of how you should counter different fallacies under different circumstances, and an approach that will work well in one situation may fail in another.
• When responding to the use of a logical fallacy, it’s important to make sure that it’s indeed a fallacy, to remember that the use of the fallacy might be intentional, and to keep in mind that just because an argument is fallacious doesn’t mean that its conclusion is necessarily wrong.
• Certain rhetorical techniques and patterns of reasoning can be described as “fallacious” even if they don’t contain a logical fallacy, because they’re used with the intent to deceive or mislead listeners.

Other articles you may find interesting:

• False Premise: When Arguments Are Built on Bad Foundations
• False Dilemmas and False Dichotomies: What They Are and How to Respond to Them
• The Fallacy Fallacy: Why Fallacious Arguments Can Have True Conclusions

Everyday Psychology. Critical Thinking and Skepticism.

What are Logical Fallacies? | Critical Thinking Basics

Logical fallacies are errors in reasoning or flawed arguments that can mislead or deceive. They often appear plausible but lack sound evidence or valid reasoning, undermining the credibility of an argument. These errors can be categorized into various types, such as ad hominem attacks, strawman arguments, and false cause correlations.

Impact on Critical Thinking, Communication, and Social Interactions

The presence of logical fallacies hampers critical thinking by leading individuals away from rational and evidence-based conclusions. In communication, they can create confusion, weaken the persuasiveness of an argument, and hinder the exchange of ideas.

In social interactions, reliance on fallacious reasoning can strain relationships, impede collaboration, and contribute to misunderstandings.

Benefits of Identifying and Managing Logical Fallacies

Learning to identify logical fallacies enhances critical thinking skills, enabling individuals to analyze arguments more effectively and make informed decisions. In communication, recognizing fallacies empowers individuals to construct more compelling and convincing arguments, fostering clearer and more meaningful exchanges.

Moreover, the ability to manage logical fallacies promotes healthier social interactions by minimizing misunderstandings, encouraging constructive dialogue, and fostering a more intellectually robust and collaborative environment.

RETURN TO THE MAIN RESOURCE PAGE: CRITICAL THINKING BASICS

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9 Logical Fallacies That You Need to Know To Master Critical Thinking

When you learn about logic, language becomes a game you can win.

William James, who was known as the grandfather of psychology, once said: “A great many people think they are thinking when they are merely rearranging their prejudices.” All of us think, every day. But there’s a difference between thinking for thinking’s sake, and thinking in a critical way. Deliberate, controlled, and reasonable thinking is rare.

There are multiple factors that are impairing people’s ability to think critically, from technology to changes in education. Some experts have speculated we’re approaching a crisis of critical thinking , with many students graduating “without the ability to construct a cohesive argument or identify a logical fallacy.”

RELATED: How to Tell if ‘Political Correctness’ Is Hurting Your Mental Health

That’s a worrying trend, as critical thinking isn’t only an academic skill, but essential to living a high-functioning life. It’s the process by which to arrive at logical conclusions. And in through that process, logical fallacies are a significant hazard.

This article will explore logical fallacies in order to equip you with the knowledge on how to think in skillful ways, for the biggest benefits. As a result, you’ll be able to detect deception of flawed logic, in others, and yourself. And you’ll be equipped to think proper thoughts, rather than simply rearrange prejudices.

What Is a Logical Fallacy?

The study of logic originates back to the Greek philosopher Aristotle (384–322 b.c.e), who started to systematically identify and list logical fallacies. The origin of logic is linked to the Greek logos , which translates to language, reason, or discourse. Logical fallacies are errors of reason that invalidate an argument. The use of logical fallacies changes depending on a person’s intention. Although for many, they’re unintentional, others may deliberately use logical fallacies as a type of manipulative behavior .

Detecting logical fallacies is crucial to improve your level of critical thinking, to avoid deceit, and to spot poor reasoning; within yourself and others. The influential German philosopher Immanuel Kant once said; “All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.”

RELATED: Fundamental Attribution Error: Definition & Examples

Throughout history, the world’s greatest thinkers have promoted the value of reasoning. Away from academia, reason is the ability to logically process information, and arrive at an accurate conclusion, in the quest for truth. Striving to be more reasonable or calm under pressure is a virtuous act. It’s a noble pursuit, one which in its nature will inspire your personal development, and allow you to become the best version of yourself.

Why Critical Thinking Is Important

It seems like humanity has never been so polarized, separated into different camps and stances; Democrats vs. Liberals, vegans vs. meat eaters, vaccinated vs. unvaccinated, pro-life vs. pro-choice. There’s nothing inherently wrong with thinking critically, and taking a stand. However, what is unusual is the tendency for people to lean into one extreme or the other, neglecting to explore gray areas or complexity.

Many of the positions people take are chosen for them. It takes a lot of effort to research a point of view. And even then, we’re faced with the challenge of information overload, fake news, conspiracy, and even credible news which is dismissed as conspiracy. Far from academic debates or politicians facing off during leadership races, the ability to share respectful dialogue is an essential part of understanding our place in the world, and maintaining human relationships.

The hot topics facing humanity aren’t going to be resolved by reactivity or over-emotionality . There should be room for all sorts of emotions to surface; it’s understandable to feel anger, grief, anxiety, etc, faced with global events. But critical thinking asks for a more reasoned, calm consideration, not getting completely carried away with emotions, but appealing to higher judgment.

Examples of When to Use Critical Thinking

It’s not always clear why critical thinking is so valuable. Isn’t it only useful for education, philosophy, science, or politics? Not quite. When applied appropriately, logic has a universal appeal in life. Examples include:

• Problem-solving : “The problem is not that there are problems,” wrote psychiatrist Theodore Isaac Rubin, “the problem is expecting otherwise, and thinking that having problems is a problem.” Life is full of problems. Fortunately, that means life is full of opportunities to problem solve. Critical thinking is an essential problem-solving skill, from managing your time to organizing your finances.
• Making optimal decisions : the more logical you are, and the less you fall into logical fallacies, the better your decision-making becomes . Decisions are the steps towards your goals, each decision making you closer to, or away from, what you really desire.
• Understanding complex subjects : with attention spans reducing due to social media and technology, it’s becoming rare to take time to attempt to understand complex topics, away from repeating what others have said. Whether through self-study or to comprehend global events, critical thinking is essential to understand complexity.
• Improving relationships : adding a dose of logic to your interactions will allow you to make better choices in relationships. Many “messy” forms of communication, from guilt-tripping to passive aggression, are illogical. By tapping into a more balanced point of view, you’ll better overcome conflict, argue your point (when necessary), or explain the way you feel.

The Most Common Logical Fallacies

When you begin to explore logical fallacies, language becomes a game. There’s a sense of having a cheat sheet in communication, understanding the underlying dynamics at play. Of course, it’s not as straightforward as a mechanical understanding — emotional intelligence, and non-verbal body language has a role to play, too. We’re humans, not computers. But gaining mastery of logic puts you ahead of the majority of people, and helps you avoid cognitive bias.

What’s more, most people fall into logical fallacies without being aware. Once you can detect these mechanisms, within yourself and with others, you’ll have an upper hand in many key areas of life, not least in a professional setting, or in any place you need to persuade or argue a point. The list is ever-growing and vast, but below are the most common logical fallacies to get the ball rolling:

1. Ad Hominem

Originating from a Latin phrase meaning “to the person,” ad hominem is an attack on the person, not the argument. This has a twofold impact — it deflects attention away from the validity of the argument, and second, it can provoke the person to enter a defensive mindset. If you’re aware of this fallacy, it can keep you from taking the bait, and instead keeping the focus on the argument.

Perhaps the most popular example of this in recent times is the viral interview between Jordan Peterson and Cathy Newman. Love him or hate him, Peterson is an embodiment of logic, sidestepping Newman’s ad hominem attacks and fallacies in a calm and controlled manner. 

2. Red Herring

You might have heard of this phrase in the context of fiction: a red herring is an irrelevant piece of information thrown into the mix, in order to distract from other relevant details, commonly used in detective stories. In a political context, you might see a politician respond to criticism by talking about something positive they’ve done. For example, when asked why unemployment is so high, they may say “we’ve made a lot of effort to improve working conditions in certain areas.”

A popular type of red herring in modern discourse is “what aboutism,” a form of counter-accusation. If the person mentioning unemployment is a fellow politician, the same politician may say: “what about unemployment rates when your party was in charge?”

3. Tu Quoque Fallacy

Closely related to the above, and in some ways, a mixture of the ad hominem and a red herring, is the tu quoque fallacy (pronounced tu-KWO-kway and originating from the Latin “you too”). This is a counter-accusation that accuses someone of hypocrisy. Rather than acknowledging what’s been said, someone responds with a direct allegation. For example, if you’re in an argument and your partner raises their voice, you may bring that to their attention, only for them to say: “you raise your voice all the time!”.

4. Straw Man

The straw man logical fallacy is everywhere, especially in dialogue on hot-topic issues, because it’s effective in shutting down someone else’s perspective. The person runs with someone’s point, exaggerates it, then attacks the exaggerated version — the straw man — seemingly in an appropriate way. For example, when your partner asks if you could do the washing up, you might respond: “are you saying I don’t support you around the house? That’s unfair.”

On the global stage, one of the big straw man arguments in recent times is the rhetoric of the anti-vaxxer, applied to resistance to mandated vaccines, social distancing, or lockdowns. The simplified term is a way of positioning someone as extreme, even if raising valid points, or looking to open dialogue about the repercussions of certain political choices, made without the option for the population to have their say.

5. Appeal to Authority

If someone in a position of authority says something is true, it must be true. This type of logical fallacy is ingrained in the psyche in childhood, where your parents’ (or adults around you) word was final. Society is moving increasingly in this direction, especially in the fields of science. But that doesn’t come without risk, as even experts are known not to get things right. 

In addition, many positions of authority aren’t always acting in pursuit of honesty or truth, if other factors (such as financial donations) have influence. While appeals to authority used to gravitate around religious leaders, a 2022 study found that, when linked with scientists, untrue statements are more likely to be believed, in what researchers call the Einstein effect .

6. False Dichotomy

Also known as the false dilemma, this logical fallacy presents limited options in certain scenarios in a way that is inaccurate. It’s closely linked to black-or-white thinking or all-or-nothing thinking, presenting two extremes without options in between. This is perhaps one of the most invasive logical fallacies in navigating life’s demands. For example, you either go to the gym or become unhealthy.

These limitations require a dose of psychological flexibility and creative thinking to overcome. They require exploring other alternatives. In the example above, that would mean looking at other ways to become healthy and exercise, such as running outdoors or going swimming.

7. Slippery Slope Fallacy

Similar to the straw man fallacy, the slippery slope is a way of taking an issue to a hypothetical extreme and then dismissing it based on what could happen. The potential of one thing leading to another, and the repercussions of that chain of events, may cause the original issue to be overlooked. For example, if you fail to set a boundary in one situation, you’ll forever be stuck in accepting certain behaviors.

The issue with this fallacy is that a valid process of critical thinking is to look at what decisions can lead to in the future. Rather than dismiss outright, however, it pays to make reasoned decisions, avoid jumping to conclusions, and see how things unfold over time.

8. Sunk Cost Fallacy

This is the logical fallacy that, when having already invested in something, you continue to invest in order to get return on your sunk costs. Although using gambling terminology (such as chasing losses on roulette) the sunk cost can apply to any area of life. The investment itself doesn’t have to be financial. For example, investing lots of time and energy into a creative project, or a relationship.

The sunk cost fallacy causes people to overlook a true and accurate analysis of the situation in the present moment, instead choosing to continue because of past decisions.

9. Hasty Generalisation

Also known as an over-generalization or faulty generalization, this logical fallacy makes general claims based on little evidence. Before writing this article, I went to a new gym, where my toiletry bag was stolen. You could argue it’s bad luck for something like that to happen on your first visit. If I decide that the gym isn’t safe, and make a hasty generalization, I may end up not going again. But what if the rate of theft in this gym was below the average in the city, and I was just unlucky? What if it wasn’t stolen, but someone absent-mindedly put it in their bag?

The opposite of a hasty generalization is to find the appropriate context for events. A logical conclusion, on the other hand, takes time. It’s reasonable, doesn’t jump in, and collects as much data as possible. If I go to the same gym, and something else is stolen, and I then see in Google reviews that others have had the same, it’d be logical for me to conclude there’s a high rate of theft.

How to Detect and Overcome Logical Fallacies

Both logic and critical thinking can be improved with practice. The knowledge of the nature of logical fallacies, and the above examples, will get you started. Deciphering when certain fallacies are active in real time is part of applied learning. Be conscious of applying the same level of rigor to your own level of reason as you do others.

There are a few components to detect and overcome logical fallacies. The first is self-awareness. As mentioned above, we’re humans, not machines. In situations where the stakes are high, we’re usually driven by factors other than logic, ulterior motives, or strong emotions that run the show. How often, when angry or triggered, do you say or act in ways you later regret?

Emotional regulation is useful in being calm enough to engage in critical thinking. But at times, logic isn’t the most skillful. For example, in conflict with a loved one, it’s more important to attempt to have compassion and understanding than to be the “most logical.” Sometimes, there are factors outside of reason that influence us, matters of the heart that can’t be captured, defined, or deconstructed by the mind.

Knowing how to apply logic, and when, is a vital skill. Through practice, over time, you’ll cultivate an even greater virtue — wisdom. A precious commodity in short supply, if you’re able to achieve wisdom and reason, the world is your oyster, a positive slippery slope to supercharge your growth.

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2.5: Logical Fallacies - How to Spot Them and Avoid Making Them

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• Athena Kashyap & Erika Dyquisto
• City College of San Francisco via ASCCC Open Educational Resources Initiative

Logical Fallacies -- Definition

As you rewrite, review, and revise your logical argument, be aware of logical fallacies, or common errors in thinking that can weaken a logical argument.

Fallacies are errors or tricks of reasoning. We can call a fallacy an error of reasoning if it occurs accidentally; we call it a trick of reasoning if a speaker or writer uses it in order to deceive or manipulate the audience. Fallacies can be either formal or informal.

(Decorative image of a traffic sign that says "Oops!") Image authored by Cripi on Pixabay. CC0: No Rights Reserved

Most formal fallacies are errors of logic: the conclusion doesn’t really follow from, or is not supported by, the premises. Either the premises are untrue or the argument is invalid. For example, the following argument contains an error in assuming that one thing and only that one thing causes a particular outcome: “Nora feeds Johnny eggplant every day, and Johnny is really healthy; therefore, we should feed our Sally more eggplant.” While it may be true that eggplant is a healthy food, Johnny’s eggplant consumption is assuredly not the only factor contributing to his health. So it does not necessarily follow that Sally should also eat eggplant every day. Formal fallacies are created when the relationship between premise and conclusion does not hold up, or when premises are unsound.

Informal fallacies take many forms and are widespread in everyday discourse. Very often they involve bringing irrelevant information into an argument, or are based on assumptions that, when examined, prove to be incorrect. For example, the following statement plays inaccurately to authority by assuming that one person only knows best, without bringing facts, multiple informed expert opinions, or relevant research into the argument: “Our governor supports a single-payer health care system for the state, so we should, too.” While the governor may have information about health care that the average citizen does not have access to, merely the fact that the governor supports a particular cause is not a reason to agree. Informal fallacies often result from the misuse of language and/or evidence.

Whether a fallacy is an error or a trick, whether it is formal or informal, its use undercuts the validity and soundness of any argument. For example, if someone defines a key term in her argument in an ambiguous, vague, or circular way, her argument will appear very weak to a critical audience.

In addition, when listeners or readers spot questionable reasoning or unfair attempts at audience manipulation, more than the author’s argument ( logos ) may be compromised. Their evaluation of the credibility of the speaker/writer ( ethos ), and perhaps their ability to connect with that speaker on the level of shared values ( pathos ), also may be compromised. At the very least, the presence of fallacies will suggest to an audience that the speaker or writer lacks argumentative skill.

Evaluating an Argument for Logical Fallacies

One way to go about evaluating an argument for fallacies is to return to the concept of the three types of support for claims: ethos, logos, and pathos.

As a quick reminder,

• Ethos is an argument that appeals to ethics, authority, and/or credibility.
• Logos is an argument that appeals to logic.
• Pathos is an argument that appeals to emotion.

Classifying fallacies as fallacies of ethos, logos, or pathos will help you both to understand their nature and to recognize them when you encounter them. Please keep in mind, however, that some fallacies may fit into multiple categories.

• Fallacies of ethos relate to credibility. These fallacies may unfairly build up the credibility of the author (or the author's allies) or unfairly attack the credibility of the author’s opponent (or allies).
• Fallacies of logos give an unfair advantage to the claims of the speaker or writer or an unfair disadvantage to his opponent’s claims.
• Fallacies of pathos rely excessively upon emotional appeals, attaching positive associations to the author’s argument and negative ones to his opponent’s position.

Evaluating an Appeal to Ethos

When you evaluate an appeal to ethos, you examine how successfully a speaker or writer establishes authority or credibility with her intended audience. You are asking yourself what elements of the essay or speech would cause an audience to feel that the author is (or is not) trustworthy and credible.

A good speaker or writer leads the audience to feel comfortable with her knowledge of a topic. The audience sees her as someone worth listening to—a clear or insightful thinker, or at least someone who is well-informed and genuinely interested in the topic.

Some of the questions you can ask yourself as you evaluate an author’s ethos may include the following:

• Has the writer or speaker cited her sources or in some way made it possible for the audience to access further information about the issue?
• Does she demonstrate familiarity with different opinions and perspectives?
• Does she provide complete and accurate information about the issue?
• Does she use the evidence fairly? Does she avoid selective use of evidence or other types of manipulation of data?
• Does she speak respectfully about people who may have opinions and perspectives different from her own?
• Does she use unbiased language?
• Does she avoid excessive reliance on emotional appeals?
• Does she accurately convey the positions of people with whom she disagrees?
• Does she acknowledge that an issue may be complex or multifaceted?
• Does her education or experience give her credibility as someone who should be listened to on this issue?

Some of the above questions may strike you as relevant to an evaluation of logos as well as ethos—questions about the completeness and accuracy of information and whether it is used fairly. In fact, illogical thinking and the misuse of evidence may lead an audience to draw conclusions not only about the person making the argument but also about the logic of an argument.

Recognizing a Manipulative Appeal to Ethos

In a perfect world, everyone would tell the truth and we could depend upon the credibility of speakers and authors. Unfortunately, that is not always the case. You would expect that news reporters would be objective and tell new stories based upon the facts. Janet Cooke, Stephen Glass, Jayson Blair, and Brian Williams all lost their jobs for plagiarizing or fabricating parts of their news stories. Janet Cooke’s Pulitzer Prize was revoked after it was discovered that she made up “Jimmy,” an eight-year old heroin addict. Brian Williams was fired as anchor of the NBC Nightly News for exaggerating his role in the Iraq War.

Others have become infamous for claiming academic degrees that they didn’t earn, as in the case of Marilee Jones. At the time of discovery, she was Dean of Admissions at Massachusetts Institute of Technology (MIT). After 28 years of employment, it was determined that she never graduated from college. However, on her website she is still promoting herself as “a sought after speaker, consultant and author” and “one of the nation’s most experienced College Admissions Deans."

Beyond lying about their own credentials, authors may employ a number of tricks or fallacies to lure you to their point of view. Some of the more common techniques are described below. When you recognize these fallacies being committed, you should question the credibility of the speaker and the legitimacy of the argument. If you use these when making your own arguments, be aware that they may undermine or destroy your credibility.

Fallacies that Misuse an Appeal to Ethos

Ad hominem : attacking the person making an argument rather than the argument itself. Latin for “argument against the person” or “argument toward the person.” Basically, an ad hominem argument goes like this: Person 1 makes claim X. There is something objectionable about Person 1. Therefore claim X is false.

False authority : relying on claims of expertise when the claimed expert (a) lacks adequate background/credentials in the relevant field, (b) departs in major ways from the consensus in the field, or (c) is biased, e.g., has a financial stake in the outcome.

Example: “Dr. X is an engineer, and he doesn’t believe in global warming.”

Guilt by association : linking the person making an argument to an unpopular person or group.

Example: “My opponent is a card-carrying member of the Communist Party.”

Poisoning the well: undermining an opponent’s credibility before they get a chance to speak.

Example: “The prosecution is going to bring up a series or so-called experts who are getting a lot of money to testify here today.”

Transfer fallacy : associating the argument with someone or something popular or respected; hoping that the positive associations will “rub off” onto the argument.

Examples: In politics, decorating a stage with red, white, and blue flags and bunting; in advertising, using pleasant or wholesome settings as the backdrop for print or video ads.

Name-calling : labeling an opponent with words that have negative connotations in an effort to undermine the opponent’s credibility.

Example: “These rabble-rousers are nothing but feminazis.”

Plain folk : presenting yourself as (or associating your position with) ordinary people with whom you hope your audience will identify; arguers imply that they or their supporters are trustworthy because they are "common people" rather than members of the elite.

Example: “Who would you vote for—someone raised in a working-class neighborhood who has the support of Joe the Plumber or some elitist whose daddy sent him to a fancy school?”

Testimonial fallacy (argument from authority) : inserting an endorsement of the argument by someone who is popular or respected but who lacks expertise or authority in the area under discussion.

Example: “I’m not a doctor, but I play one on TV”—a famous example of a celebrity endorsement for a cough syrup (Deis, 2011, n.p.).

The most general structure of this argument runs something like the following: Person A claims that Person A is a respected scientist or other authority; therefore, the claim they make is true.

Evaluating an Appeal to Logos

When you evaluate an appeal to logos, you consider how logical the argument is and how well-supported it is in terms of evidence. You are asking yourself what elements of the essay or speech would cause an audience to believe that the argument is (or is not) logical and supported by appropriate evidence.

To evaluate whether the evidence is appropriate, apply the STAR criteria: how S ufficient, T ypical; A ccurate, and R elevant is the evidence?

Recognizing a Manipulative Appeal

Diagramming the argument – identifying the main claim and the main supporting points or premises – can help you determine if an appeal to logos is manipulative. Write out the main claim or conclusion. Then identify the supporting claims or premises. Are the premises true? Does the conclusion follow logically from the premises? Is there sufficient, typical, accurate, and relevant evidence to support the reasoning? Is the speaker or author attempting to divert your attention from the real issues? These are some of the elements you might consider while evaluating an argument for the use of logos.

Pay particular attention to numbers, statistics, findings, and quotes used to support an argument. Be critical of the source and do your own investigation of the “facts.” Maybe you’ve heard or read that half of all marriages in America will end in divorce. It is so often discussed that we assume it must be true. Careful research will show that the original marriage study was flawed, and divorce rates in America have steadily declined since 1985 (Peck, 1993). If there is no scientific evidence, why do we continue to believe it? Part of the reason might be that it supports the commonly held idea of the dissolution of the American family.

Deductive Logic

An argument using deductive logic is one that works from the top to the bottom. It begins with what is known as a "major premise," adds a "minor premise," and attempts to reach a conclusion. A major premise is a statement that comments about a large group, a minor premise refers to a single member, and the conclusion attempts to prove that because this single member is a part of the larger group, it must, therefore, also have the trait named in the major premise.

For example:

Now, if it is true that men are tall, and that Bob is a man, then we can safely infer that Bob must be tall. However, beware the logical fallacy. Though it may be true that in certain cultures men are, on average, taller than women, certainly this is not always the case. Being that our major premise is not altogether true, we can now say that this argument is flawed. Further, we might ask what our definition of "tall" is. Tall is different if we are talking about the average population, different for basketball players. Also, what is a man? Are transgendered individuals included? We see that the problem becomes far more complex the more we look into it.

Inductive Logic

While some would argue that a deductive argument works from the top down, toward a conclusion, and that an inductive argument works from the bottom up. This is mildly misleading. What is meant by this is that an inductive logical argument begins with a firm affirmation of truth, a conclusive statement. By getting the audience to agree with this statement, the argument moves to the next "logical" step. It proceeds in this manner until the argument has led you from one seemingly reasonable conclusion to another that you may not have originally agreed with. Take the following as an example. (Move through the argument slowly, making sure you understand and agree with each step in the process -- and please forgive the religious content, you'll come to see it is irrelevant anyway).

The human soul is inherently free. This is its very nature. We are confined to our mortal, earthly bodies, but our souls must be kept free, or the nature of the soul is entirely negated. If one chooses to believe in a soul, they can only believe that it embraces this (vague idea of) freedom.

At conception, a child is given a soul. Some may argue that that happens after birth, but if those very same persons are pro-life, they confuse their arguments. Thus, if someone is pro-life, and believes in a soul, they must believe in the freedom of that soul, and also accept that the soul is granted upon conception.

A soul cannot die. By the same means by which it is free over the body, a soul claims immortality while the body decomposes and is ended. To deny that a soul is immortal is again to deny the very essence of a soul. Thus, if someone is pro-life, and believes in a soul, they must believe in the freedom of that soul, the immortality of the soul, and also accept that the soul is granted upon conception.

A soul cannot be born. It is immortal and cannot die, it is not earthly, it forever exists, and cannot be born. There are tales in Greek mythology of Athena’s birth, yet she is born from her father’s head a fully decorated woman. She was not born. She existed previously, as Milton writes the Son in Paradise Lost. If one accepts the Bible’s teachings, there can be no reincarnation, no other form of birth, or rebirth. Thus, if someone is pro-life, and believes in a soul, and does not accept reincarnation, they must believe in the freedom of that soul, the immortality of the soul that is always and forever (which cannot be born and cannot die), and also accept that the soul is granted upon conception.

A soul being always an essence, and not being able to be reincarnated, can only exist outside of the body, somewhere, until the act of conception occurs. That soul must then be placed in the body that was forever intended to receive it, as it belongs nowhere else. The soul is fated to that one body. Thus, if someone is pro-life, and believes in a soul, and does not accept reincarnation, namely a practicing Catholic, they must also believe in the freedom of the soul, and in the concept of fate. Fate, however, completely opposes the idea of freedom. One cannot then believe in a soul, for it immediately enforces a belief in fate which directly negates the belief in the soul. If our actions are written in a Divine plan, we are not free to make our own choices. Every action has been scripted.

Don't worry, it must be that you were meant to read this.

Here's a sample inductive argument by Ben Doberstein.

Having seen this, some might say that the argument defeats Catholicism from an atheist standpoint. Others might find that it argues for the secularization of religion. Still, there are ways in which it supports Catholicism at the same time.

Though the argument might seem as if it is disagreeing with the Catholic religion, and some would agree that it is, we must always be looking for the logical fallacy. Upon closer inspection, you may notice that all this argument truly does, in one reading of the text, is to explain the complexity of God through the mind of a human. Catholicism has argued since the beginning that God is impossible to fully explain using the conceptions of man. In that way, this argument only supports that conclusion.

Be aware that there will be logic fallacies hidden in almost every argument. If there is more than one side to an argument, such as in religious or political debates, it is most likely because the argument is impossible to prove. Hence, there is a logical fallacy in the argument.

Fallacies that misuse appeals to logos or attempt to manipulate the logic of an argument are discussed below.

Fallacies that Misuse an Appeal to Logos

Hasty generalization: jumping to conclusions based upon an unrepresentative sample or insufficient evidence.

Example: “10 of the last 14 National Spelling Bee Champions have been Indian American. Indian Americans must all be great spellers!”

Appeal to ignorance—true believer’s form: arguing along the lines that if an opponent can’t prove something isn’t the case, then it is reasonable to believe that it is the case; transfers the burden of proof away from the person making the claim (the proponent).

Example: “You can’t prove that extraterrestrials haven’t visited earth, so it is reasonable to believe that they have visited earth.”

Appeal to ignorance—skeptic’s form: confusing absence of evidence with evidence of absence; assumes that if you cannot now prove something exists, then it is shown that it doesn’t exist.

Example: “There’s no proof that starting classes later in the day will improve the performance of our high school students; therefore, this change in schedule will not work.”

Begging the question: circular argument because the premise is the same as the claim that you are trying to prove.

Example: “This legislation is sinful because it is the wrong thing to do.”

False dilemma: misuse of the either/or argument; presenting only two options when other choices exist

Example: “Either we pass this ordinance or there will be rioting in the streets.”

Post hoc ergo propter hoc: Latin phrase meaning “after this, therefore because of this”; confuses correlation with causation by concluding that an event preceding a second event must be the cause of that second event.

Example: “My child was diagnosed with autism after receiving vaccinations. That is proof that vaccines are to blame.”

Non-sequitur: Latin for “does not follow”; the conclusion cannot be inferred from the premises because there is a break in the logical connection between a claim and the premises that are meant to support it, either because a premise is untrue (or missing) or because the relationship between premises does not support the deduction stated in the claim.

Example (untrue premise): “If she is a Radford student, she is a member of a sorority. She is a Radford student. Therefore she is a member of a sorority.”

Smoke screen : avoiding the real issue or a tough question by introducing an unrelated topic as a distraction; sometimes called a red herring .

Example: “My opponent says I am weak on crime, but I have been one of the most reliable participants in city council meetings.”

Image by Mark Klotz on flickr CC BY-NC: Attribution-NonCommercial

The red herring is as much a debate tactic as it is a logical fallacy. It is a fallacy of distraction and is committed when a listener attempts to divert an arguer from his argument by introducing another topic. This can be one of the most frustrating, and effective, fallacies to observe.The fallacy gets its name from fox hunting, specifically from the practice of using smoked herrings, which are red, to distract hounds from the scent of their quarry. Just as a hound may be prevented from catching a fox by distracting it with a red herring, so an arguer may be prevented from proving his point by distracting him with a tangential issue.

Straw man: pretending to criticize an opponent’s position but actually misrepresenting his or her view as simpler and/or more extreme than it is and therefore easier to refute than the original or actual position; unfairly undermines credibility of claim if not source of claim.

Example: “Senator Smith says we should cut back the Defense budget. His position is that we should let down our defenses and just trust our enemies not to attack us!”

Evaluating an Appeal to Pathos

People may be uninterested in an issue unless they can find a personal connection to it, so a communicator may try to connect to her audience by evoking emotions or by suggesting that author and audience share attitudes, beliefs, and values—in other words, by making an appeal to pathos. Even in formal writing, such as academic books or journals, an author often will try to present an issue in such a way as to connect to the feelings or attitudes of his audience.

When you evaluate pathos, you are asking whether a speech or essay arouses the audience’s interest and sympathy. You are looking for the elements of the essay or speech that might cause the audience to feel (or not feel) an emotional connection to the content.

An author may use an audience’s attitudes, beliefs, or values as a kind of foundation for his argument—a layer that the writer knows is already in place at the outset of the argument. So one of the questions you can ask yourself as you evaluate an author’s use of pathos is whether there are points at which the writer or speaker makes statements assuming that the audience shares his feelings or attitudes. For example, in an argument about the First Amendment, does the author seem to take it for granted that the audience is religious?

Recognizing a Manipulative Appeal to Pathos

Up to a certain point, an appeal to pathos can be a legitimate part of an argument. For example, a writer or speaker may begin with an anecdote showing the effect of a law on an individual. This anecdote will be a means of the author gaining an audience’s attention for an argument in which they use evidence and reason to present their full case as to why the law should/should not be repealed or amended. In such a context, engaging the emotions, values, or beliefs of the audience is a legitimate tool, the effective use of which should lead you to give the author high marks.

An appropriate appeal to pathos is different than trying to unfairly play upon the audience’s feelings and emotions through fallacious, misleading, or excessively emotional appeals. Such a manipulative use of pathos may alienate the audience or cause them to “tune out”. An example would be the American Society for the Prevention of Cruelty to Animals (ASPCA) commercials featuring the song “ In the Arms on an Angel ” and footage of abused animals. Even Sarah McLachlan, the singer and spokesperson featured in the commercials, admits that she changes the channel because they are too depressing (Brekke, 2014).

Even if an appeal to pathos is not manipulative, such an appeal should complement rather than replace reason and evidence-based argument. In addition to making use of pathos, authors must establish their credibility (ethos) and must supply reasons and evidence (logos) in support of their position. An author who essentially replaces logos and ethos with pathos alone should be given low marks.

See below for the most common fallacies that misuse appeals to pathos.

Fallacies that Misuse an Appeal to Pathos

Appeal to fear: using scare tactics; emphasizing threats or exaggerating possible dangers.

Example: “Without this additional insurance, you could find yourself broke and homeless.”

Appeal to guilt and appeal to pity : trying to evoke an emotional reaction that will cause the audience to behave sympathetically even if it means disregarding the issue at hand.

Example: “I know I missed assignments, but if you fail me, I will lose my financial aid and have to drop out.”

Appeal to popularity (bandwagon): urging tthe audience to follow a course of action because “everyone does it.”

Example: “Nine out of ten shoppers have switched to Blindingly-Bright-Smile Toothpaste.”

Slippery Slope: making an unsupported or inadequately supported claim that “One thing inevitably leads to another.” This may be considered a fallacy of logos as well as pathos but is placed in this section because it often is used to evoke the emotion of fear.

Example: “We can’t legalize marijuana; if we do, then the next thing you know people will be strung out on heroin.”

Appeal to the people: also called stirring symbols fallacy; the communicator distracts the readers or listeners with symbols that are very meaningful to them, with strong associations or connotations.

Example: This fallacy is referred to in the sentence “That politician always wraps himself in the flag.”

Appeal to tradition: people have done it a certain way for a long time; assumes that what has been customary in the past is correct and proper.

Example: “A boy always serves as student-body president; a girl always serves as secretary.”

Loaded-Language and other emotionally charged uses of language: using slanted or biased language, including Goodness terms, devil terms, euphemisms, and dysphemisms.

Example: In the sentence “Cutting access to food stamps would encourage personal responsibility,” the "goodness" term is “personal responsibility.” It might seem as if it would be hard to argue against “personal responsibility” or related "goodness" terms such as “independence” and “self-reliance.” However, it would require a definition of “personal responsibility,” combined with evidence from studies of people’s behavior in the face of food stamp or other benefit reductions, to argue that cutting access to food stamps would lead to the intended results.

Fallacies can crop up whenever definitions, inferences, and facts are at issue. Once we become familiar with fallacies we may start to see them everywhere. That can be good and bad. Since persuasion is ever-present, it is good to be on guard against various hidden persuaders. But whether a persuasive strategy is considered fallacious may be dependent on context. For example, we expect advertisements, political speeches, and editorials on public policy or ethical issues to try to sway us emotionally.

However, as a writer of logical argument, your task is to evaluate your draft in order to identify and eliminate inappropriate logical fallacies, which often try to argue through emotional means, personal attack, or inappropriate evidence and conclusions. Your purpose, as a writer of logical argument, is to get your reader to see the value in what you’re asserting, to get that person to say “I understand and accept the validity of your point of view,” even though he may still not agree.

Identifying Hasty Generalizations

A generalization is a reasonably true statement based on statistically valid data. A hasty generalization is a statement that is true in general but may not be true in any particular case. A generalization becomes a hasty generalization when the statement is assumed to be true about an individual or when the generalization is statistically invalid. Hasty generalizations are one of the most common logical fallacies.

Decide whether the following statements are generalizations or hasty generalizations:

A. Dogs developed from wolves.

B. You’ll be a victim of a crime if you are out between 1 a.m. and 3 a.m.

C. Crime happens more often in cities than in suburbs.

D. Women are more neurotic than men (according to a fired Google employee manifesto).

E. Pit bulls are killers.

F. Billionaires are greedy.

Identifying Logical Fallacies and Appeals

Individually or in groups, identify the logical fallacies (by name) or appeals in the following statements.

1. Pilots claim to have seen unidentified flying objects (spacecraft from other planets). Pilots are trained in observation and are reliable, so UFOs must exist.

2. The universe has all the properties to support life; therefore, it was designed specifically to support life.

3. What are skeptics of alternative medicines afraid of?

4. There is no evidence to show ghosts exist, so ghosts do not exist.

5. Mammals live on land. Whales are mammals. Therefore, whales must live on land.

6. The number of transistors in a dense integrated circuit doubles approximately every two years.

7. More people in the world smoke than in the past. The rate of people dying from lung cancer is declining. Smoking does not cause lung cancer.

8. Drinking alcohol increases one’s risk for breast cancer. Katie drinks four glasses of wine per week. She will develop breast cancer.

9. Computers are the brains of machines, so people should not need much sleep for their brains to work properly.

10. The earliest remains of Homo erectus are in Africa and Asia, so the species originated in one of those places.

11. The extinction of large mammals will inevitably lead to the extinction of humans.

12. Humans are destroying Earth, so we should colonize Mars so we can survive.

13. We don’t know how placebos work, so they must not work.

Logical Fallacies Review

The following video, while relatively lengthy, clearly explains many common logical fallacies such as hasty generalization, slippery slope, and more. As such, it provides a good review of the fallacies that you should be identifying and editing out of your logical argument essay drafts.

Video: Logical Fallacies by US Represented. All Rights Reserved. Standard YouTube license.

Contributors:

• Adapted from College Writing , authored by Susan Oaks, provided by Empire State College, SUNY OER Services. License : CC BY-NC-SA:

This page last updated on June 5, 2020.

Guide to Logical Fallacies in Business

150 critical thinking mistakes to avoid, publisher description.

In the high-stakes arenas of business, a single logical misstep could be the difference between a breakthrough and a breakdown. "Guide to Logical Fallacies in Business: 126 Critical Thinking Pitfalls to Avoid" offers a lifeline for the modern business professional, an invaluable resource to navigate through the deceptive waters of faulty reasoning. This book is more than just a guide; it's a critical thinking crusade against the misconceptions and manipulations rife in the corporate world: Fallacy Breakdown: Each of the 126 fallacies comes with a detailed exploration of its structure and impact on business dynamics.Real-World Applications: Contextual examples bring the fallacies to life, demonstrating their influence on decisions, strategies, and negotiations.Defensive Strategies: Arm yourself with robust mental frameworks to deflect the allure of erroneous logic.Argument Arsenal: Learn how to dismantle fallacious reasoning presented by others with precise counterarguments.Interactive Engagement: Sharpen your skills through exercises that challenge you to spot and correct flawed reasoning.Practical Exercises: Practice rearticulating common business assertions into logically sound statements, strengthening your communicative prowess. This book doesn't just list fallacies; it equips you with the tools to detect, debate, and debunk them. Whether you're a seasoned executive or an aspiring leader, mastering the content within these pages will give you the edge in a world where critical thinking is king. Step into a realm where clarity conquers confusion and where reasoning reigns supreme. Forge your path to logical mastery and business excellence with "Guide to Logical Fallacies in Business."

The Power of Critical Thinking in the Life of the High Schooler | Interview w/ Kathy Gibbens How to Homeschool in High School

Our world (especially as teens) is full of so much information! We are confronted daily with bad thinking, propaganda, and emotional reasoning - it can be hard to manage! Today we have the privilege of hearing from Kathy Gibbens, homeschool mom and host of the "Filter it Through a Brain Cell Podcast" (a podcast focused on teaching critical thinking skills to every listener)! We cover everything from defining critical thinking and the most common fallacies we face as teens today to discovering how we can stay rooted in truth amidst this ever-changing culture! Resources mentioned: Fallacy Detective Master Books  - Introduction to Logic Memoria Press  - Traditional Logic Connect with Mrs. Gibbens: Filter it Through a Brain Cell: Podcast Filter it Through a Brain Cell: Instagram Follow How to Homeschool in High School on Instagram and Facebook Email questions to [email protected] Music by FASSounds from Pixabay

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