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The Fallacy Detective

The Fallacy Detective
Price: $22.00
  • Workbook Edition (2015): Includes spaces for readers to write in their answers to the exercises.
  • (2015) Sample Lesson (PDF)

What is a fallacy? A fallacy is an error in logic – a place where someone has made a mistake in his thinking.

These are fallacies:

“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 new book, The Fallacy Detective, must do a good job teaching logic. It has been on the bestseller list for months.”

We wrote this book to meet 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. We divided the most common fallacies and propaganda techniques into thirty-eight lessons. We explain how you can spot fallacies, and we give exercises to stretch your abilities for detecting fallacies.
--Geared for ages twelve and older – we suggest using The Fallacy Detective before advancing onto more difficult logic programs.
--Includes The Fallacy Detective Game, giving you and your friends an entertaining way to spot and make up your own examples of fallacies.
--Can be used before or after The Thinking Toolbox
--Cartoons to illustrate the logical fallacies discussed, including Peanuts, Dilbert, Calvin and Hobbes, and several original cartoons

This book is for fallacy detectives. We’ve designed this book to be a handy-dandy text for learning to spot the errors in thinking that you meet everyday on the street, in the newspaper, or on television – or errors you make yourself.

Book Contents

Introduction: What Is a Fallacy?

The Inquiring Mind

1. Exercise Your Mind

2. Love to Listen

3. Opposing Viewpoints

Avoiding the Question

4. Red Herring Fallacy

5. Recognizing Red Herrings

6. Special Pleading

7. Ad Hominem Attack

8. Genetic Fallacy

9. Tu Quoque

10. Faulty Appeal to Authority

11. Appeal to the People

12. Straw Man

Making Assumptions

13. The Story of Aroup Goupta

14. Assumptions

15. Circular Reasoning

16. Equivocation

17. Loaded Question

18. Slippery Slope

19. Part-to-Whole

20. Whole-to-Part

21. Either-Or

Statistical Fallacies

22. What Is a Generalization?

23. Hasty Generalization

24. What Is an Analogy?

25. Weak Analogy

26. Post Hoc Ergo Propter Hoc

27. Post Hoc Ergo Propter Hoc in Statistics

28. Proof by Lack of Evidence


29. What Is Propaganda?

30. Appeal to Fear

31. Appeal to Pity

32. Bandwagon

33. Exigency

34. Repetition

35. Transfer

36. Snob Appeal

37. Appeal to Tradition and Appeal to Hi-Tech

38. Find Some Propaganda on Your Own

The Fallacy Detective Game

Answer Key


Customer Reviews:

: Review of The Fallacy Detective by Kathy Davis at homeschoolbuzz.com
One of the most important gifts any parents can give their child is wisdom. The book of Proverbs tells us to acquire wisdom, pursue it, love it, and guard it.

The Fallacy Detective, teaching classical logic from a Christian worldview, is one practical tool that will help you and your children down the path to wisdom. With thirty-six lessons you will be well on your way to a discerning, inquiring mind. The book explains such things as what are fallacies, assumptions, generalizations, analogies, and propaganda. But more than that, it will teach you good reasoning skills in a biblical way. Written in an intelligent, yet easy to grasp manner, the Bluedorn brothers have produced a fine book here. Peppered with humor and an occasional comic strip, your children will enjoy using this book and playing the Fallacy Detective game to help them apply what they’ve learned.

The book is “self-teaching” with lessons that are short, interesting and fun. However, it is recommended that lessons be done together with your children, as discussions are crucial to help develop thinking skills and abilities to spot bad reasoning.

If you homeschool for reasons of faith or worldview, it's important for your children to be able to discern truth from lie, spot fallacies and defend their view. The Fallacy Detective will help you to equip your children to stand firm against the moral relativism of this world.

~Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. – 1 Peter 3:15

: Reviews on blogs
The Fallacy Detective, written by Hans and Nathaniel Bluedorn, is a book designed for teens or adults that teaches how to spot common errors in reasoning. The goals for this book are clearly laid out in the introduction. When the reader has completed this book he should be able to put a high value on good reasoning, know how to spot many forms of bad reasoning and know how to avoid using many fallacies in his own reasoning.

The authors provide a vision of Christian logic in which they appeal to the need for Christians to strive for a higher standard of reasoning, in order to attain greater ability in discernment. Logic is an important foundation for the science of discernment. Thus they seek to define good reasoning in a biblical way. "Logic is the science of thinking the way God thinks - the way Jesus taught us to think" (page 14).

The book contains thirty-six lessons which progress from the most common and basic fallacies, to statistical fallacies and even propaganda. All those terms I have not heard since my university Critical Thinking courses are present as well as some that are commonly used and misused: red herring, ad hominem, tu quoque, appeal to the people, part-to-whole, whole-to-part and so on. Each lesson is followed by several questions which allow the reader to apply what he has just learned. I was glad to see that the questions are cumulative, meaning that what has been taught in previous lessons is continually reviewed in the application questions for subsequent chapters.

The authors write in a style that will appeal to teens and young people. The text is interspersed with comics (such as Calvin & Hobbes, Peanuts and Dilbert) and anecdotes. It is also a funny book, as there are many places where the authors turn to humor to make the book enjoyable. A typical lesson may begin similar to this one, which discusses weak analogies: "Let's say...you are a budding scientist wanting to write your graduate thesis on the long term effects of Pop-Tarts on humans. The only problem is, you can't find enough people who are willing to eat thirty-four Pop-Tarts a day for one year" (page 131).

Can learning logic be fun? With The Fallacy Detective it appears that it can be. I thoroughly enjoyed this book and would recommend it to anyone who wants to improve his reasoning skills. While its primary usefulness will be for teenagers, adults will also enjoy it and benefit from the lessons. If you homeschool your children, this may be a useful title.

This is the second book I have read from the Bluedorns. The first was the The Thinking Toolbox. The Bluedorns sent me this book to review. It is titled The Fallacy Detective and was written by Nathaniel Bluedorn & Hans Bluedorn.

They again have done a wonderful job of laying out the fallacies in a way that is easy to understand. It is broken down into 36 lessons, so you can do 1 per day if you wish. The problems they have at the end of each section are great and build on each other. Don’t forget to try out the Fallacy Game which they provide at the end of the book. You’ll have a blast while learning.

I have been using this book to watch my own writings and the comments I receive on my blog so I will improve. It has been very helpful. I read a section a day and then try to apply it to my writings and questions from commenters. I have learned to recognize many of the fallacies quickly and not get drawn into the traps that others are trying to set for me. I don’t always succeed at that, but I am improving thanks to the Bluedorns. Keep up the good work guys.

I would recommend this book to all writers or politicians, whether you are a novice or an expert. There is always some little tidbit of knowledge to learn. I have learned a lot. I would stick to the recommendation on this book that it book be read or studied by teenagers and above. Most younger kids would not understand the differences between the fallacies.

: Reviews from kids
I love your book! I never knew how much fun logic was until I read your book. Please write back. P.S. I am 12 years old.—Paul Muenzler

: Reviews from parents
I LOVED Fallacy Detective and so did my children (3 teenage boys and a 9 y.o. girl!) Rebekah is constantly calling me on my different fallacies! Thank you for making logic so easy to understand! Looking forward to using your second book! You have done a fantastic job! — Kathryn Zellers

I just wanted to let you know how much my thirteen year old son and I are enjoying The Fallacy Detective! It's the first book that he reaches for each school day. It has been particularly relevant as we just had a provincial election. There were plenty of opportunities to identify Red Herrings, Ad Hominem attacks, and more, during the election campaign. It is a delight to see my son apply his new-found knowledge to real life situations.—Rosanne Conner, Canada

I just finished reading The Fallacy Detective and now I am reviewing/summarizing all the definitions again. This is an excellent book to get started with in order to make logic real (applicable) in someone's life. I also started working some "think a minutes" workbooks with my daughter (age 9). Thank you again for your good resources and for pointing me to better thinking skills.—Bill Bernhart

My kids have greatly enjoyed Hans and Nathaniel's The Fallacy Detective. They now think that Logic is a really fun subject—I hope that future studies do not destroy the delight they now take in the subject!—Janet

My kids and I are going through your Fallacy Detective book – even my 9 year old is getting something out of it!—Colette

We are LOVING Fallacy Detective as a family, and my son is wondering if the boys will be writing a "sequel" or "volume 2" of it. It is our best seller this year of any item we carry.—Kathy from Family Bookshelf

Just a note of congratulations to a great book! We bought the book recently and are enjoying the lessons, the style and format. It is a pleasure. We are very pleased that a local Church bookshop is in contact with you - now we can more easily order your books.—Sonja from South Africa

Just want to thank you for the book! I'm going through it with my 10yodd and 9yods, and I'm amazed at what they are getting out of it! They are younger than the recommended age, but we are doing Ancient History, so I decided to just do a chapter or two to introduce them to the idea. We've kept on going: we're on chapter 25, and they are not only enjoying it, they are applying it (catching themselves -- and me!-- in fallacies throughout the day). Thanks for a great book and your great website! L Ann, homeschooling since 1986

I gave my son a copy for christmas. He is 13. It was meant to be an 'aside' sort of gift, just a little something extra, but guess what! Wow! He got ahold of that book and wouldn't put it down for a week. Now, literally everyday, he asks if we can go through it together, and he is leading his brother and me through it lesson by lesson. I will be standing at the stove stirring a pot of soup and J... will be perched on a stool with E... on the counter, book in hand asking us questions. Quite often the littler one listens in and answers when he can. They are all expert critics of the local news media! This has been the very best book I have given him in a long time. Thank you for putting together such a fun and well layed out book. Fun really is the key. We all enjoy it immensely and I have to say I just have to smile and truly love it when E... comes into the kitchen book in hand or pulls it out of his backpack while we're driving to music lessons (or where ever) so we can go over a lesson together. He knows I'm a captive audience at those times and he loves to share what he's enjoying...your book is it. Thanks, Cynthia

: Review in 100 Top Picks for Homeschool Curriculum by Cathy Duffy

: Review at woodburyschool.com
The Fallacy Detective:Thirty-Six Lessons in How to Recognize Bad Reasoning by brothers Hans and Nathaniel Bluedorn teaches critical thinking from a distinctly Christian worldview.

Critical Thinking: That's one of those topics we all know is essential for our children to master, but also one of the most challenging to teach. Part of the process is giving children great books to read, and giving them time to think about what they are reading. By using supplemental curricula like The Fallacy Detective, you can add some formality to the study.

Written in a very engaging style, this book is as enjoyable to read as it is educational. There are comic strip examples of the fallacies, starring Bluedorn creations "Nuna and Toodles," as well as guest appearances by Peanuts, Dilbert, and Calvin and Hobbes, which make them not only easier to understand, but also more memorable. Building on the Bluedorns' use of comics, we had our oldest daughter (like a detective) find examples of fallacies in our collection of Calvin and Hobbes anthologies. This was a great way to reinforce the lessons and was fun as well!

The combination of the Bluedorns' writing style and the book's organization enable this book to be used effectively children 12 years old and up.

: Review from the Timberdoodle book catalog
So excited were we about discovering The Fallacy Detective, we immediately assigned it to all five of our children. But with just one book, scheduling was one more task I didn’t need. So we opted to make it part of our read-aloud time at night. Now in our best moments, none of us are especially sharp, and evenings just seemed to exasperate our already humble condition, but to the authors’ credit, this book was abundantly easy to use, and engaging to boot. Doing it as a family gave us some friendly competition as we raced to answer the questions. It also allowed us to be on the ‘same page’ as we encounter and discuss the fallacies we confront every day. Although the authors recommend this book for older children, Pearl was 8 when we started it and we did not feel any of the topics were inappropriate – heart breaking perhaps, but not improper. You may feel differently, so we urge you to stay one chapter ahead if you are using this book with younger children.

: Review at midwestbookreview.com
Collaboratively written by Nathaniel Bluedorn and Hans Bluedorn for a Christian readership, The Fallacy Detective: Thirty-Six Lessons On How To Recognize Bad Reasoning presents common-sense guidelines to reasonable discourse that readers of all faiths and backgrounds can understand and appreciate. Indeed, The Fallacy Detective is a first-rate guide to common logic pitfalls and errors in human decision making. From red herrings and ad hominem attacks that avoid the issue at hand altogether, to fallacious hidden assumptions of "either-or" in a world filled with multiple possibilities, hasty generalizations and statistical fallacies, as well as the dark power and abuse of propaganda, The Fallacy Detective covers an immense range of illogical appeals that are as frustrating as they are distressingly effective. Highly recommended for the non-specialist general reader, The Fallacy Detective is a superbly written and presented primer for making informed conclusions in a world filled with lies, deceits, and misconceptions.

: Review by Jay Wile
. . . Thank you for sending me your book, The Fallacy Detective. I thought it was very well done. I liked how you blend easy-to-understand examples, humor, and Christian thinking together and at the same time teach the reader many of the standard terms and propositions of logic. Also, the thought questions you have at the end of each chapter are very good. Also, I hope I am not being too bold here, but in the discussion of ad hominem attacks, I think I see some of my biology course coming through. That really gave me great pleasure to see that you could use some of what you learned in that course to teach logic! —Jay Wile

: Review from the Veritas Press book catalog
The brothers Bluedorn have created a very clever tool to meet an extraordinary gap in the materials necessary to teach Logic and provide a complete education in the dialectic stage. Studying Informal Logic, as the study of fallacies is sometimes described, will do more to teach the student to think clearly, reason well and spot errors in the reasoning of others than any other activity. This book compliments the Introductory Logic and Intermediate Logic texts to provide a thorough study of the discipline.

: Review by Martha Robinson at HomeschoolChristian.com
The Fallacy Detective offers a simple and straightforward study of informal fallacies. Subtitled "Thirty-Six Lessons on How to Recognize Bad Reasoning," the book seeks to teach one "to recognize logical fallacies which you meet every day in the street, in the newspaper, or in your work."

The authors are the grown sons of Harvey and Laurie Bluedorn of Trivium Pursuit and were trained via the Bluedorn's vision of classical home education. Nathaniel and Hans Bluedorn present the book from a Christian perspective.

The introductory chapter explains the importance of logic for Christians, and examples throughout the book use issues, such as abortion, conservation, and politics, that concern conservative families.

Lessons are brief and simple, lasting only a few pages. Each one addresses a particular fallacy and explains examples of that type of fallacy in detail. For example, in the "Propaganda" chapter, the following exercise is presented:

'Gun manufacturers should do something about all those guns we have lying around. My grandson was brutally murdered last summer by another child with a gun.'

Another example in the "Generalization" section is as follows: 'No matter what they say, all salesmen don't care a bit about the people they sell to. They just want your money.'

These exercises and examples are designed to generate thought and discussion. An answer key is provided in the back of the book.

Recommendation: The Fallacy Detective offers a beginning look at one part of informal logic or "critical thinking." This book does not teach formal (deductive or inductive) logic. Written with the Bluedorns' more relaxed style, this product offers a pleasant way to begin logic studies. The authors recommend the book for ages 13 and up. The informal writing style used is sure to be appealing and understandable to children even younger, but because of the issues discussed in the exercises and examples, I would respect the Bluedorns' recommendation on the age range.

The content as well as the cover illustration of Toodles, the fallacy detective dog, by Johannah Bluedorn, make The Fallacy Detective a memorable book and a nice addition to your dialectic aged student's curriculum.

: Review from The Tech, Massachusetts Institute of Technology's oldest and largest newspaper.
I’m always delighted when two sides that seem mutually opposed come together in harmonious agreement. I’m even more delighted when I’ve taken one of those sides.

In this case, I write of the efforts of Nathaniel and Hans Bluedorn, brothers from Iowa who advocate homeschooling and create educational materials from a Christian worldview. The fruit of the latest Bluedorn effort is a short text, The Fallacy Detective, designed to be a primer in logic for older children --specifically, homeschooled Christian children, though the book is intended for anyone who wants to explore the subject. . . .

. . . I find it wonderful that the Bluedorns, among others, are actively reinvigorating the religious world with a healthy dose of independent thought . . .

—Andrew C. Thomas

: Review from Conservative Book Club
Finally, an easy and practical start to learning logic — Written to meet the needs of homeschoolers and teachers, The Fallacy Detective is a fun and non-intimidating text for teaching logic and critical thinking to children. Its thirty-six lessons teach children to detect the logical fallacies and propaganda techniques most commonly encountered in everyday life, especially in the media, advertising and politics. The goal of the book is to help children recognize and refute bad reasoning, and to discover that logic can be fun. And unlike many critical thinking texts, this one does not promote political correctness; in fact, examples throughout the book use issues, such as abortion and gun control, that concern conservative and Christian families.

Each lesson has exercises for students, with an answer key at the back. The book ends with the Fallacy Detective Game, where kids can have fun with their siblings and friends (and parents!) who have been learning logic with them. Twenty cartoons drawn from Peanuts, Dilbert, and other cartoon classics amusingly illustrate the fallacies and propaganda techniques discussed. Best of all, The Fallacy Detective is self-teaching -- children 13 and up should be able to work through this book without needing any outside help.

: Review by Izzy Lyman at icky.blogspot.com
I was recently sent a delightful book called The Fallacy Detective by Nathaniel Bluedorn and Hans Bluedorn. Both authors are in their twenties and have a homeschooling background.

It teaches readers - via thirty-six lessons - how to recognize bad reasoning. A very useful skill. The book explains fallacies, like a red herring, as well as propaganda techniques. It includes exercises, an answer key, and cartoons. The Bluedorns recommend it for ages 13 through adult. (This adult even learned about a post hoc ergo propter hoc.)

The book is marketed as a "Christian view of logic" because it does not have a politically correct bent. However, I think non-believers will feel comfortable with the majority of the content.

: Reviewed by Merrilee Defoe at eho.org
Do you know what a fallacy is? I'm a little embarrassed to admit that I didn't even know there was such a word, let alone know its meaning. For those of you in the same boat, a fallacy is an error in logic, a place where someone has made a mistake in their thinking.

Seeing a need for higher standards of reasoning in Christians as well as in themselves, authors and brothers Nathaniel and Hans Bluedorn wrote The Fallacy Detective.

Written for Christians from the age 13 and up, The Fallacy Detective provides you with a genuine Christian worldview on logic as well as why it is so important for Christians to strive for higher standards of reasoning. There are thirty-six lessons in all; each one has a brief lesson to read followed by exercises to work through. There are also Scripture verses in several of the lessons. After reading through a lesson and completing the exercises that follow it, you can check your answers in the back of the book, and then proceed to the next lesson. By the time you finish all thirty-six lessons you will know enough about fallacies to play The Fallacy Detective Game, which you will also find at the back of the book.

This really is a very practical book to have on your shelf, even if you don't think you need it!

: Review at homeschoolreviews.com/reviews/fallacydetective.html
This book is set up like a chapter book, introducing one idea at a time in a progression to more difficult ideas. This is great book for an informal introduction to the ideas of logical thinking, especially for children and parents with no prior experience. The publisher recommends this book for ages 13 and up, because of the political and ethical nature of the current events we face today. But they DO keep it fun. My 6th & 7th graders were ready for this introduction to the subject of Logic and had a blast! They truly couldn't wait to learn something new. It opened up their minds to listen more closely to what they read and hear. They love playing "Detective" and love to identify "Fallacies," especially in others. ha! The book is written by two homeschool boys who are knowledgeable and very witty. They keep the subject exciting by introducing one topic each chapter, and progressing to more complex logic, building on the previous lessons. Always informative, professional, serious and witty - they manage to mix in all the right ingredients.

: Awards
The Fallacy Detective was a finalist in ForeWord Magazine's 2003 Book of the Year Awards in the Philosophy category.


: Review in Mary Pride's Practical Homeschooling May/June 2005 issue
The Fallacy Detective is a thoroughly Christian self-teaching introduction to Logic. The authors, Nathaniel and Hans Bluedorn, start off by explaining why you should want to learn this material. They make it all so clear by numerous easy-to-understand examples. . . . Each lesson is three to five pages long and written in a very readable style. Parents will enjoy reading this aloud to their children, but children of the appropriate ages can also greatly benefit by studying it on their own. Reviewed by Melissa Worcester

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