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The Fallacy Detective: Thirty-Six Lessons on How to Recognize Bad Reasoning, 2nd Edition
What is a fallacy? A fallacy is an error in logic a place where someone has made a mistake in his thinking. A cloud is 90% water. A watermelon is 90% water. Therefore, since a plane can fly through a cloud, a plane can fly through a watermelon. This book meets the needs of parents who want a do-able text for introducing logic and critical thinking to their children. -Fun to use -- not dry like a math textbook. -Self-teaching -- not intimidating, starts students with skills they can use right away. -Each lesson has exercises for students, with an answer key at the back. -Covers logical fallacies and propaganda techniques. -Geared for ages twelve and older. -Includes cartoons to illustrate the logical fallacies discussed, including Peanuts, Dilbert, Calvin and Hobbes.
227 pages, Paperback
First published June 30, 2002
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Displaying 1 - 30 of 152 reviews
April 30, 2016
The Fallacy Detective is written primarily for homeschoolers, especially Christian homeschoolers. Most college graduates who took philosophy/logic will recognize the fallacies and will appreciate the simple and practical description of those fallacies and the examples of each. There are exercises at the end of each short chapter to check for understanding.
The book is a mix of hits and misses, good logic with weak examples, unintended fallacies offered up as good logic, great examples mixed up with examples that aren't. The book would be useful for anyone looking for an easy to understand treatment of the major formal and informal fallacies and would be an introduction tool for helping children (or adults) to think critically. Adults whose formal education didn't include logic, philosophy, or critical analysis and writing would like this book because it presents these things in a way that doesn't get bogged down in complexities and hard to follow explanations.
However, the authors occasionally insert Bible references, depending upon on Christian faith as examples of good logic or as proof that something is true. Faith's apologists often commit these easy to fall into errors. But any faith based religion is, by the very nature of that "faith," not legitimate logic or philosophy. When the authors say, "the Bible says ..." or "this isn't true because the Bible says ..." they commit a logical fallacy trying to counter a logical fallacy. Simply replacing "the Bible says" with "the Quran says ..." or "Buddha says ..." or "The Vedas say ... " will reveal the error. Faith can't be used to "prove" logic, or anything else. It ceases to be faith in that case; faith is the substance of things hoped for, the evidence of things not seen.
The book is a mix of hits and misses, good logic with weak examples, unintended fallacies offered up as good logic, great examples mixed up with examples that aren't. The book would be useful for anyone looking for an easy to understand treatment of the major formal and informal fallacies and would be an introduction tool for helping children (or adults) to think critically. Adults whose formal education didn't include logic, philosophy, or critical analysis and writing would like this book because it presents these things in a way that doesn't get bogged down in complexities and hard to follow explanations.
However, the authors occasionally insert Bible references, depending upon on Christian faith as examples of good logic or as proof that something is true. Faith's apologists often commit these easy to fall into errors. But any faith based religion is, by the very nature of that "faith," not legitimate logic or philosophy. When the authors say, "the Bible says ..." or "this isn't true because the Bible says ..." they commit a logical fallacy trying to counter a logical fallacy. Simply replacing "the Bible says" with "the Quran says ..." or "Buddha says ..." or "The Vedas say ... " will reveal the error. Faith can't be used to "prove" logic, or anything else. It ceases to be faith in that case; faith is the substance of things hoped for, the evidence of things not seen.
August 10, 2018
Are you tired of pointless, loud arguments? Do you want to know where you're going wrong with your reasoning? Read this book. Thank me later.
July 12, 2024
Excellent primer for youth and adults on logical fallacies. Humorous, from a Christian perspective (not overt), with good examples. I only need more practice and experience to remember and identify these. I wonder if a workbook would help.
2024: This is such a good book. Better than Wilson’s Bestiary and cheaper than CAP’s Art of Argument. No need to do the expensive curricula versions with workbooks and videos. It’s just informal logic—fallacies. Read with Callie and Carson.
2024: This is such a good book. Better than Wilson’s Bestiary and cheaper than CAP’s Art of Argument. No need to do the expensive curricula versions with workbooks and videos. It’s just informal logic—fallacies. Read with Callie and Carson.
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April 2, 2011LOL! This April fools' day, the joke's on me! You could say I made some false assumptions about this book when I picked it out from the library, and then went recommending it (at least putting it on my Education Resources book list) before thoroughly reading it. I was pleased to flip through and see headings on ad hominem, red herring, straw man, faulty appeal to authority, loaded question, appeal to fear, either-or, etc. I assumed the purpose of the book was to teach "how to recognize bad reasoning," and simply that. I missed the pages in the intro. (and the info. on the back cover), that the book's goal was to not only do this, but do it from a distinctly "Christian" perspective. Once I realized this, I thought it would be interesting to see what, from the authors' perspectives, that entailed. While the book does a nice job of explaining many of the logical fallacies listed, it also displays some unintentional logical fallacies and assumptions supporting what some would label the Christian viewpoint (as if there were only one) on numerous controversial topics.
These can simply be used as more opportunities for discussion, exposure to various viewpoints, and analysis of logical fallacies, if the reader catches them.
However, some things are presented so misleadingly (for instance the characterization of the theory of evolution and it's debate) as to make me have a hard time fully recommending this book.
These can simply be used as more opportunities for discussion, exposure to various viewpoints, and analysis of logical fallacies, if the reader catches them.
However, some things are presented so misleadingly (for instance the characterization of the theory of evolution and it's debate) as to make me have a hard time fully recommending this book.
July 27, 2011
I'd heard such rave reviews about this book throughout the home-schooling community, but was disappointed when I finally purchased it. Although I'm sure there are excellent logical arguments, I was immediately turned off by what I felt was the superiority complex of the authors.
June 7, 2015
This was one of the best school books ever!
June 1, 2012
Although the book is labeled as "for ages twelve through adult" and I purchased this book to teach informal logical fallacies to my high school daughters, my nine-year-old son read and loved it as well. The book is well written in a humorous, conversational style, replete with comics that illustrate the various fallacies, and has exercises that build on and review everything covered in each section. And while it is not difficult to read, the exercises are challenging, and even as an adult who had learned the fallacies before, I still failed to get a perfect score on any of them. I intend to use it again next school year with my to-be seventh and fifth graders. It is a great curriculum choice for upper elementary through high school.
January 15, 2022
This book was so fun!!!!
Only 3 stars because I didn't always agree with the answers and a lot of the examples weren't that great. They also implied firstborn children are headstrong, stubborn and spoiled so here you go you asked for it ;-)
Only 3 stars because I didn't always agree with the answers and a lot of the examples weren't that great. They also implied firstborn children are headstrong, stubborn and spoiled so here you go you asked for it ;-)
January 15, 2025
When you can recognise, identify, and name the ways in which others use propaganda and bad reasoning to manipulate, you have more power.
Instead of being a gullible victim, you will be an aware, intelligent, and informed individual.
We make a lot of fallacies in our speech, and I discovered that in order to speak without error you must treat your speech the way a college English teacher edits a paper. Of course we can't do that all the time, but the value of clarity, backing up claims, saying what we mean, etc. will all greatly benefit our communication.
Helpful book, but a bit over explained at times. Sometimes there are multiple falacy names for a very similar error (whole to part, part to whole, for example)
I rate based on the quality of books comparitivley, so while this was a good book to read once and maybe occasionally come back to, it is not a classic that I will read over and over again.
A list of the fallacies honestly provides the same info as the whole book, save for the helpfulness of the exercises.
Instead of being a gullible victim, you will be an aware, intelligent, and informed individual.
We make a lot of fallacies in our speech, and I discovered that in order to speak without error you must treat your speech the way a college English teacher edits a paper. Of course we can't do that all the time, but the value of clarity, backing up claims, saying what we mean, etc. will all greatly benefit our communication.
Helpful book, but a bit over explained at times. Sometimes there are multiple falacy names for a very similar error (whole to part, part to whole, for example)
I rate based on the quality of books comparitivley, so while this was a good book to read once and maybe occasionally come back to, it is not a classic that I will read over and over again.
A list of the fallacies honestly provides the same info as the whole book, save for the helpfulness of the exercises.
May 12, 2015
A nice introduction to the fallacies, written by local, former homeschooled brothers. We liked the simple, easy to read explanations of the fallacies, many of which have become a common part of our language around home. Watch out, your kid may call you on a few. ;)
December 15, 2023
We used this as a homeschool text this year. The youngest regular participant was 9, and that went well. It's a fun introduction to these fallacies, and it's silly enough that the kids looked forward to it. Some of the fallacies could use more explanation, and some of the questions in the exercises were more ambiguous that would have been ideal (though debates can be part of the fun), but it was an excellent way to start conversations about more logical thinking.
May 24, 2018
Reading this in class at Co-op. An excellent introduction to logic, I only wish that the examples were not so US-centric. The children are definitely learning though, and works well in a 30m class. I also do a sheet of logic cartoons to go with the chapter topic - v easy to find with Google, lots of great ones out there.
February 2, 2016
I did this last year, and it was a ton of fun. Yay for logic! :P I'm pretty common-sense/logic minded, so this is definitely my thing.
January 18, 2018
this was a sumwhat boring book to me.
January 9, 2019
A must for middle school and high school for critical thinking in a non-overwhelming way!
December 6, 2021
Highly recommended
Read
January 22, 2021I read the first few chapters. As an adult who likes logic and wanted to see how a clear intro would look like this is very much not for me at all. This is for small kids in 6th grade. Maybe up to 8th grade at most if they want to play around with simple logical puzzles. It’s very low level.
The chapters in the workbook version have very short intros to some logical assumption. These intros seem to be very weak and often pointless as they are largely just children’s book level stuff focused on storytelling. The writing is good though. Then after each mini chapter there is a row of about 10 questions about some logical assumption. The questions can go like this: “Little Bobby says he can’t put the toys back as he can’t remember where they go.” Then the real answer as revealed in the back of the book is: “Little Bobby tends to forget where toys go when he is lazy.” As you can see you don’t just have to use logical tools to find the right solutions you have to understand regular social settings, normal white lies and other social tricks and then apply them to “solve” the logical problems. That’s not the kind of rational logic I seek more knowledge about. Maybe if they had made clear that Little Bobby is at home playing with his old toys their answer would be more logical. I just figured he was at the doctor's office or something.
Either way as you can see this is a book for absolute beginners and it doesn’t really strictly use rational logical methods to solve issues, but is rather a book to make kids think about social settings. It’s very fine for younger teens, but as an adult I can’t rate it highly. I haven’t read much of it at all, but such weird issues at the start obviously make me just want to stop reading. I’m seeking something more rational and hard. The workbook version is basically a discussion starter in class settings, nothing more. It does introduce logical fallacies, but these kind of soft intros are not worth much as it's fluffy and unfocused in how it tackles the issues.
Introduction: What Is a Fallacy? The Inquiring Mind
1 Exercise Your Mind 14
2 Love to Listen 18
3 Opposing Viewpoints 22
Avoiding the Question
4 Red Herring Fallacy 28
5 Recognizing Red Herrings 34
6 Special Pleading 39
7 Ad Hominem Attack 43
8 Genetic Fallacy 49
9 Tu Quoque 53
10 Faulty Appeal to Authority 57
11 Appeal to the People 64
12 Straw Man 69
Making Assumptions
13 The Story of Aroup Goupta 76
14 Assumptions 82
15 Circular Reasoning 88
16 Equivocation 94
17 Loaded Question 100
18 Slippery Slope 107
19 Part-to-Whole 113
20 Whole-to-Part 119
21 Either-Or 125
Statistical Fallacies
22 What Is a Generalization? 134
23 Hasty Generalization 141
24 What Is an Analogy? 150
25 Weak Analogy 157
26 Post Hoc Ergo Propter Hoc 166
27 Post Hoc Ergo Propter Hoc in Statistics 172
28 Proof by Lack of Evidence 178
Propaganda
29 What Is Propaganda? 188
31 Appeal to Pity 198
32 Bandwagon 202
33 Exigency 206
34 Repetition 210
35 Transfer 214
36 Snob Appeal 219
37 Appeal to Tradition and Appeal to Hi-Tech 224
38 Find Some Propaganda on Your Own 230
The chapters in the workbook version have very short intros to some logical assumption. These intros seem to be very weak and often pointless as they are largely just children’s book level stuff focused on storytelling. The writing is good though. Then after each mini chapter there is a row of about 10 questions about some logical assumption. The questions can go like this: “Little Bobby says he can’t put the toys back as he can’t remember where they go.” Then the real answer as revealed in the back of the book is: “Little Bobby tends to forget where toys go when he is lazy.” As you can see you don’t just have to use logical tools to find the right solutions you have to understand regular social settings, normal white lies and other social tricks and then apply them to “solve” the logical problems. That’s not the kind of rational logic I seek more knowledge about. Maybe if they had made clear that Little Bobby is at home playing with his old toys their answer would be more logical. I just figured he was at the doctor's office or something.
Either way as you can see this is a book for absolute beginners and it doesn’t really strictly use rational logical methods to solve issues, but is rather a book to make kids think about social settings. It’s very fine for younger teens, but as an adult I can’t rate it highly. I haven’t read much of it at all, but such weird issues at the start obviously make me just want to stop reading. I’m seeking something more rational and hard. The workbook version is basically a discussion starter in class settings, nothing more. It does introduce logical fallacies, but these kind of soft intros are not worth much as it's fluffy and unfocused in how it tackles the issues.
Introduction: What Is a Fallacy? The Inquiring Mind
1 Exercise Your Mind 14
2 Love to Listen 18
3 Opposing Viewpoints 22
Avoiding the Question
4 Red Herring Fallacy 28
5 Recognizing Red Herrings 34
6 Special Pleading 39
7 Ad Hominem Attack 43
8 Genetic Fallacy 49
9 Tu Quoque 53
10 Faulty Appeal to Authority 57
11 Appeal to the People 64
12 Straw Man 69
Making Assumptions
13 The Story of Aroup Goupta 76
14 Assumptions 82
15 Circular Reasoning 88
16 Equivocation 94
17 Loaded Question 100
18 Slippery Slope 107
19 Part-to-Whole 113
20 Whole-to-Part 119
21 Either-Or 125
Statistical Fallacies
22 What Is a Generalization? 134
23 Hasty Generalization 141
24 What Is an Analogy? 150
25 Weak Analogy 157
26 Post Hoc Ergo Propter Hoc 166
27 Post Hoc Ergo Propter Hoc in Statistics 172
28 Proof by Lack of Evidence 178
Propaganda
29 What Is Propaganda? 188
31 Appeal to Pity 198
32 Bandwagon 202
33 Exigency 206
34 Repetition 210
35 Transfer 214
36 Snob Appeal 219
37 Appeal to Tradition and Appeal to Hi-Tech 224
38 Find Some Propaganda on Your Own 230
June 17, 2017
All of us, including children, should be capable of picking out false presentations, particularly because we are in America, a country saturated with commercial enterprises seeking a sale and politicians seeking office. An understanding of simple logical fallacies is a top priority for any citizen. Too many Americans are duped because they don't recognize the falsity of messages directed their way from a multitude of sources from the White House down to the local car dealership.
The Fallacy Detective is written by two home school advocates. They claim it can be used with anyone 12 years of age or older. Each chapter lays out a type of fallacy, a fallacy being the use of language to give a sense of logic while being illogical.
Following the explanation of a given fallacy are many examples of the fallacy in action, little scenarios of dialog in which readers are to identify the fallacy. These examples are well crafted, not at all simplistic and clearly illustrate fallacies as we find them in daily life. The setting might be a family argument, one friend trying to convince another or a politician making a claim. The exercises are challenging (put on your thinking cap!) but help one to see clearly how often we encounter people trying to fool us into accepting what they have to say, at our cost.
This best way to educate any child about fallacies involves the parents pointing them out as they are encountered in daily life. There's no substitute for on-the-job training and for a child, gaining understanding is a job that is too easily missed when parents are not attentive to the need for guidance. I would recommend this book, as the authors do, to anyone 12 or older. If you are a parent, a quick overview is recommended. In fact, were I back to the days of being a young parent, I would read the book, take liberally from it and then weave it into daily living with my children rather than taking it out as a formal exercise in learning.
By the way, those of us who went through the fanatic and frantic period of the George W. Bush push for war in Iraq will appreciate the chapter on "exigency" in which rushing the subject to do something RIGHT NOW is used as a way to decide an issue with little or no reason behind it.
The Fallacy Detective is written by two home school advocates. They claim it can be used with anyone 12 years of age or older. Each chapter lays out a type of fallacy, a fallacy being the use of language to give a sense of logic while being illogical.
Following the explanation of a given fallacy are many examples of the fallacy in action, little scenarios of dialog in which readers are to identify the fallacy. These examples are well crafted, not at all simplistic and clearly illustrate fallacies as we find them in daily life. The setting might be a family argument, one friend trying to convince another or a politician making a claim. The exercises are challenging (put on your thinking cap!) but help one to see clearly how often we encounter people trying to fool us into accepting what they have to say, at our cost.
This best way to educate any child about fallacies involves the parents pointing them out as they are encountered in daily life. There's no substitute for on-the-job training and for a child, gaining understanding is a job that is too easily missed when parents are not attentive to the need for guidance. I would recommend this book, as the authors do, to anyone 12 or older. If you are a parent, a quick overview is recommended. In fact, were I back to the days of being a young parent, I would read the book, take liberally from it and then weave it into daily living with my children rather than taking it out as a formal exercise in learning.
By the way, those of us who went through the fanatic and frantic period of the George W. Bush push for war in Iraq will appreciate the chapter on "exigency" in which rushing the subject to do something RIGHT NOW is used as a way to decide an issue with little or no reason behind it.
November 24, 2021
This book was so fun!!!!
Only 4 stars because I didn't always agree with the answers and they implied firstborn children are headstrong, stubborn and spoiled so here you go you asked for it ;-)
(I read the newer version)
Only 4 stars because I didn't always agree with the answers and they implied firstborn children are headstrong, stubborn and spoiled so here you go you asked for it ;-)
(I read the newer version)
Want to read
June 21, 2018This review says The Fallacy Detective is better than The Amazing Dr. Ransom's Bestiary of Adorable Fallacies.
December 7, 2020
Great intro to fallacies and lots of fun. Occasionally I disagreed with their assessment of a fallacy, but overall it was a good resource.
July 7, 2023
AO Y7 ✔️
Well written, great sense of humor, and I liked the short chapters. I will never see advertisements the same way! 😂
Well written, great sense of humor, and I liked the short chapters. I will never see advertisements the same way! 😂
July 18, 2024
My grown children still talk about this book and “The Thinking Toolbox.” Time well spent…
August 19, 2024
Helpful for kids and adults of all ages: 11, 15, 18, and 40-something. ;)
March 8, 2025
Critical thinking is important and we all can use a refresher course on it regularly. However, this book may not be the best choice for everyone. Learning the names of three dozen different kinds of fallacies is an unnecessary challenge imo. Esp. when some are almost indistinguishable; for example I don't understand the distinction between 'appeal to the people' and 'bandwagon.'
Working through the book is somewhat fun, but it took a long time, and got difficult at the end... especially because I disagreed with several of the examples' answers. Otoh, the disagreement was, after all, about the jargon or terminology - the Bluedorns' and I agreed that the example given was fallacious in some way or another.
But the book did give me some things to think about. And the cartoons are fun. And there is a summary list in the back. And it's not too much of a "Christian" book.
"Ad hominem also occurs when somebody accuses his opponent of having bad motives."
Working through the book is somewhat fun, but it took a long time, and got difficult at the end... especially because I disagreed with several of the examples' answers. Otoh, the disagreement was, after all, about the jargon or terminology - the Bluedorns' and I agreed that the example given was fallacious in some way or another.
But the book did give me some things to think about. And the cartoons are fun. And there is a summary list in the back. And it's not too much of a "Christian" book.
"Ad hominem also occurs when somebody accuses his opponent of having bad motives."
September 28, 2025
Read this one as a youngster and really opened my eyes on how to argue properly and logically about truth. Great for 14 and under kids and probably some adults who missed any formal logic teachings growing up.
July 17, 2015
I found The Fallacy Detective by Nathaniel Bluedorn and Hands Bluedorn to be a helpful resource. You will never listen to an advertisement, debate, persuade or write the same way again!
I think that believers should know their logic -- after all, God is a God of order! I appreciate the Bluedorns' heart behind the book. In their words: "We see a need for Christians to strive for a higher standard of reasoning. We believe God wants his people to become aware of their lack of discernment, and logic is an important part of the science of discernment. For instance, many Christians adopt beliefs and practices without properly evaluating the arguments which are used to support them. We need to rediscover the way of the Bereans, who searched the Scriptures daily to see if the apostles’ teachings were true (Acts 17:10-11).” -Nathaniel and Hands Bluedorn (The Fallacy Detective)
This book is broken up in an easy read of 36 lessons, introducing different fallacies and bad reasoning. They discuss the different kinds of assumptions, statistical fallacies and propaganda and provide examples and a clear, easy-to-understand explanation of each. The book is written for young students, but I think anyone would benefit from a read, even just a skim to brush up. The Bludorns write with humor, clarity and will hold the interest of anyone who desires to be wiser in the area of reasoning. The Fallacy Detective changed the way I think about logic.
Read the full review here: http://www.atime2write.com/2015/06/bo...
I think that believers should know their logic -- after all, God is a God of order! I appreciate the Bluedorns' heart behind the book. In their words: "We see a need for Christians to strive for a higher standard of reasoning. We believe God wants his people to become aware of their lack of discernment, and logic is an important part of the science of discernment. For instance, many Christians adopt beliefs and practices without properly evaluating the arguments which are used to support them. We need to rediscover the way of the Bereans, who searched the Scriptures daily to see if the apostles’ teachings were true (Acts 17:10-11).” -Nathaniel and Hands Bluedorn (The Fallacy Detective)
This book is broken up in an easy read of 36 lessons, introducing different fallacies and bad reasoning. They discuss the different kinds of assumptions, statistical fallacies and propaganda and provide examples and a clear, easy-to-understand explanation of each. The book is written for young students, but I think anyone would benefit from a read, even just a skim to brush up. The Bludorns write with humor, clarity and will hold the interest of anyone who desires to be wiser in the area of reasoning. The Fallacy Detective changed the way I think about logic.
Read the full review here: http://www.atime2write.com/2015/06/bo...
October 8, 2015
The Fallacy Detective is an amazing book which helps us to identify the fallacy we make in our reasoning in a day to day life. Even before understanding the different types of fallacies, it is necessary to build the "questioning mind". We should stretch our mind by doing mental hard work so that it's ready when we want to use them.
Listening is an art which we should practice in order to understand other people's opinions, question our own position and accept if we don't know anything. Also, it is very critical to look at an argument from multiple viewpoints.
The book covers different types of fallacies that we make while avoiding the questions, making assumptions, statistical fallacies and how we use different propaganda in order to make others believe in our ideas
Listening is an art which we should practice in order to understand other people's opinions, question our own position and accept if we don't know anything. Also, it is very critical to look at an argument from multiple viewpoints.
The book covers different types of fallacies that we make while avoiding the questions, making assumptions, statistical fallacies and how we use different propaganda in order to make others believe in our ideas
May 18, 2017
We read a short story in my class called, "Love is a Fallacy." Last year one of my students said I should get The Fallacy Detective, because she recognized the fallacies in the short story, because her mom had read and discussed the book with her when she was younger. So I asked for this book when we had to choose one.
I found it very interesting to read through the exercises in reasoning. Some of the exercises seemed too easy and others too hard--but a good mix of all. I hope to be able to use some of them with the short story in the future, especially for those students who like the concept and want to explore it further.
I found it very interesting to read through the exercises in reasoning. Some of the exercises seemed too easy and others too hard--but a good mix of all. I hope to be able to use some of them with the short story in the future, especially for those students who like the concept and want to explore it further.
July 29, 2011
I used this book to teach critical thinking skills to my children. This book is a good introduction, but nothing outstanding, and there are websites on the internet that offer a lot more on logical fallacies than this one did. I supplemented the learning by having my preteens search for examples of the fallacies in newspapers and advertising. The 'letters to the editor section of the paper was a particularly rich source.
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