42 Fallacies for Free

As a free gift to the readers of the Talking Philosophy blog, I offer my 42 Fallacies. It is a PDF book containing definitions and examples of 42 common fallacies. I assure you that it is worth every penny. For Kindle fans, it is also available for 99 cents (or the equivalent in other countries) in the US, the UK and elsewhere. 

Perhaps the best (and meanest) use was suggested by a friend of mine: email the file to someone with the subject “You really need this.” This could lead to a discussion on the ethics of using a philosophy book in an act of cruelty.





The book contains the following fallacies.

Ad Hominem
Ad Hominem Tu Quoque
Appeal to the Consequences of a Belief
Appeal to Authority
Appeal to Belief
Appeal to Common Practice
Appeal to Emotion
Appeal to Popularity
Appeal to Fear
Appeal to Flattery
Appeal to Novelty
Appeal to Pity
Appeal to Popularity
Appeal to Ridicule
Appeal to Spite
Appeal to Tradition
Begging the Question
Biased Generalization
Burden of Proof
Circumstantial Ad Hominem
Fallacy of Composition
Confusing Cause and Effect
Fallacy of Division
False Dilemma
Gambler’s Fallacy
Genetic Fallacy
Guilt by Association
Hasty Generalization
Ignoring a Common Cause
Middle Ground
Misleading Vividness
Peer Pressure
Personal Attack
Poisoning the Well
Post Hoc
Questionable Cause
Red Herring
Relativist Fallacy
Slippery Slope




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  3. Thanks, Mike. I’m about to replace my computer, but when I get my new one, one of the first things I’ll download is your book on fallacies. A useful tool.

  4. Argumentics. I cut your post, not Mike. Because you’re rude and boorish. Plus you’ve got a stupid username.

    Constructive criticism is one thing. But your kind of condescension will not be tolerated on this blog.

  5. Perhaps one oughtn’t to look a gift horse in the mouth, but it seems to me that you get off to a very bad start with this statement on the first page:

    If the premises actually provide the required degree of support for the conclusion, then the argument is a good one. A good
    deductive argument is known as a valid argument and is such that if all its premises are true, then its conclusion must be true.

    Consider the following arguments. Argument 1:

    (1) The moon is made of cheese. (Premise)
    (2) The moon is made of cheese. (Conclusion)

    Argument 2:

    (1) The moon is made of cheese. (Premise)
    (2) The moon is not made of cheese. (Premise)
    (3) Pigs fly. (Conclusion)

    Both arguments are deductively valid. Both are therefore good arguments, and good deductive arguments, by your declared standard. But surely neither one is a good argument.

  6. @MKR

    Those arguments are not of a valid logical form.




    are not deductivley valid, sorry. The first is a tautology, not a valid argument and the second, well, I don’t know what it is.

  7. Actually my last comment was utter bollocks, a tautology is a valid argument, just one which offers no support for its conclusion. The second argument really is’nt valid though.

  8. Adam, it is logic 101 that any argument from contradictory premises is deductively valid. I omitted the intermediate steps, but here they are in schematic form:

    (1) P (Premise)
    (2) ~P (Premise)
    (3) P v Q (From (1))
    (4) Q (From (2) and (3))

  9. Adam, please disregard the reference to “Logic 101,” which was needless snark.

  10. @MKR
    “if all its premises are true”
    “(1) The moon is made of cheese. (Premise)”

    So it’s true that the moon is made of cheese?

  11. You don’t need symbols to figure out the two arguments offered by MKR are false. The first because the premise isn’t true; the second because a statement which is self-contradictory can’t be true because it’s nonsensical. No degree in logic required.

  12. EFQ, you are right, I kinda felt something was fishy as I was writing the comment, and now I feel kinda stupid. I’ll take it as a sign that I need to go back and brush up on my logic fundamentals.


    You are bringing up problems with the soundness of the arguments, it’s completely seperate from their validity, he never said they were sound arguments.

  13. Peter, what Adam says is correct. Look again at Dr. Labossiere’s text, especially the second paragraph under the heading “Fallacies and Arguments,” and notice that he defines “good argument” (badly, in my judgment) and “deductively valid argument” (correctly) before he has made any mention of the truth of premises.

    Adam, I hope that by “EFQ” you meant to refer to me (MKR) and we are now in agreement.

    I think that Dr. LaBossiere has conflated the question “What makes an argument a good one?” with the question “What are the standards by which an argument is logically evaluated?” Logic has traditionally been concerned solely with the relation of premises to conclusions in arguments; it does not concern itself with whether premises are true or false, probable or improbable, rationally warranted or unwarranted, or accepted or not accepted by the audience to whom the argument is addressed. Yet these are surely features that are material to the goodness of an argument.

    I believe that he could get himself out of his difficulty by simply replacing the phrase “good argument” with “good argument in logical respects” or “logically good argument.”

  14. MKR,

    Argument 1 is valid. If the premise is true, then the conclusion must be true. After all, they are the same. As such it is a good argument from the standpoint of logic.

    Argument 2 cannot have all true premises and a false conclusion, so it would also be valid. The test for validity can be seen as trying to show the argument invalid (with a truth table for example). Doing this would involve showing that is has all T premises and a F conclusion. Since 1 contradicts 2, this is impossible. So, as odd as it might seem, it would be a good argument because it will never yield a false conclusion from all true premises. It will, of course, never be sound.

    Perhaps I should have distinguished more explicitly between the goodness of the logic and the goodness (truth) of the premises.

  15. I’m inclined to think that it is fine to refer to a deductively valid argument as a good argument. Of course, this might merely because “good argument” is commonly used that way in the standard texts (such as Critical Thinking by Moore & Parker). Of course, we could all be mistaken in our usage.

    In my classes, I usually begin by distinguishing between good and bad arguments by drawing the distinction between fallacious and non-fallacious reasoning. I then go on to discuss how to assess the plausibility of the claims made in the premises. My reason for this approach is that the students usually have no idea about the distinction between the quality of reasoning (logically good) and the quality of the premises. So, I just start off fairly generally by talking about a good argument and then get into the slightly more technical aspects.

  16. @Peter
    >The first because the premise isn’t true

    That really doesn’t matter here Peter!


  17. My reason for this approach is that the students usually have no idea about the distinction between the quality of reasoning (logically good) and the quality of the premises. (Mike LaBossiere)

    I don’t doubt that. Most people are slow even to grasp the distinction between a premise and a conclusion, or the distinction between whether an argument is good and whether the conclusion is one that they like!

  18. This is really quite good. Thank you. A part of me was waiting for a punch line in there somewhere, like so much satire posted these days, but no. It’s simply good stuff.

    I’m going to pop it onto my Kindle (thanks for the PDF version, btw)… my guess is that I should need to read it a few more times.

    Thanks again!

  19. Risk managment is not a fallacy.

    Slippery slope has many examples of being true.

  20. Bah,

    Sure, a slippery slope can turn out to have a true conclusion. However, getting a claim right and arriving at it by the basis of good reasons are two different things.

  21. thank you so much for this wonderful gift! I’ve been looking for this exact sort of book for a while now!

  22. Fallacies « PHILOSOPHY IN A TIME OF ERROR - pingback on September 14, 2010 at 3:43 pm
  23. “As a free gift to the readers of the Talking Philosophy blog…”

    Yo, Michael, you’ll want to trash this common redundancy. ALL gifts are free. That’s what a gift is. Free.


  24. Don:

    In some cultures, giving a gift creates an obligation in the other to repay with a gift of similar or greater value. Thus, in those cultures, there are no free gifts for those who participate
    in the game of giving and receiving gifts.

  25. Don,

    The day before I posted the blog I received one of those pieces of junk mail promising me a “free gift.” I couldn’t resist using that phrase myself.

    On a more serious note, not all gifts are free-they often come with strings and hidden costs. Of course, you could then argue that such “gifts” are not really gifts, but rather something else.

  26. To Mike, CC all;

    It’s been a couple of months since I downloaded the PDF book, and quite a few interesting things have happened in my life. The timing was good, in part due to the elections that just took place. My own friends, as well as commentators, and speech-writers, have all neatly fallen into certain categories of your book, with their speech. Strangely, when people use rational, non-fallacied arguments, no one seems interested in what they have to say. It’s almost as if they throw out a fallacy just to stir it up, and to break the ice. And at that point, people start talking.

    On the other hand, if I say “if we do X, then Y will probably happen.” And the reaction is a spoken (or unspoken) “oh” or “oh yeah?”

    I wonder if people are outrageous, either on purpose or out of habit, just to grease the conversation, or maybe to “sell papers”?

    When someone accidentally releases toxic fumes, it is called an industrial accident. When someone releases toxic fumes in a subway with bad intent, it is called terrorism. In a similar thought, when someone is discussing a topic and they use a fallacy in their persuasion, it is helpful to point out why their reasoning is flawed. But if they are using one of these fallacies, intentionally trying to “win the argument” instead of showing why a conclusion is sound, this PDF document is an incredibly handy anti-terrorism weapon that I have used more than once. And for that, I thank you.

    Oh, and the other thing that has happened during that time is this thread. It is fascinating to me, watching all the directions that this thread is trying to go, instead of sticking to the topic at hand. This may be a larger symptom of society today, possibly an object example of one or more of those forty-two things. Why would people consciously attempt to verbally assault you, become banned, and then try to create a new account to continue the assault, and argue something like the reason for the reason for the reason?

    Harumph. We all know how those kind of people act.

  27. it is helpful to point out why their reasoning is flawed. But if they are using one of these fallacies, intentionally trying to “win the argument” instead of showing why a conclusion is sound.

  28. In some cultures, giving a gift creates an obligation in the other to repay with a gift of similar or greater value. Thus, in those cultures, there are no free gifts for those who participate
    in the game of giving and receiving gifts.

  29. The biggest fallacy is the life they have some public characters certain parts of the planet … I like the idea of ​​download and read your book … I could serve to classify certain characters I have in mind

  30. Plissee Jalousien

    You need symbols to figure out the arguments offered. The first because the premise isn’t true the second because a statement which is self contradictory can’t be true because its nonsensical.

  31. DYSPEPSIA GENERATION » Blog Archive » 42 Fallacies for Free - pingback on December 18, 2011 at 8:05 am
  32. Lucio Gutiérrez

    Just an observation about the Hasty generalization fallacie:
    If X% of all observed A’s are B’s, then it is correct to conclude that X% of all A’s are B’s. It’s not even a conclusion; it’s the observation itself. The fallacie would be to think that since X% of all observed A’s are B’s, therefore Y% of all A’s are B’s, Y being much larger than X.
    Very useful book, by the way. Thanks for making it free!

  33. Lucio Gutiérrez

    OK, I get it. The observed A’s is not the whole population of A’s. My mistake… if you can delete my previous comment, please do, he he.

  34. This is great – thank you very much.

  35. Andy,
    You are welcome. If you haven’t done so already, you can also get 30 More Fallacies and Moral Methods from this site as free PDF files.

  36. dawit merhatsidk

    this is interesting material that i ever read. please add the formal fallacies and make it complate

  37. this is interesting book that i have ever read. thanks for printing such like this material.

  38. this is an interesting book that i have ever read concerning fallacies. thanks mike

  39. Mike,

    I’ve come to the logical conclusion that your books are excellent. Period. End of story. Great style, easy to understand. Thank you for making this information available.

    Keep up the great work! 🙂

    Best regards,
    Alan W
    Dallas, TX

  40. Free book on logical fallacies! « Critical Reaction - pingback on May 20, 2012 at 2:03 am
  41. Thank you. I bought it on my Kindle.

  42. Peg,

    Thanks-I hope your find it useful.

  43. Where to Find Fallacies? « deuteronomy316 - pingback on October 24, 2012 at 7:04 pm
  44. Rhetorical & Logical Fallacies to Avoid when Debating - pingback on November 9, 2012 at 11:57 pm
  45. Thanks Mike. I have half read the book already. It is easy to read and precise.

  46. You are welcome-I hope you find it useful.

  47. Isn’t Appeal to Popularity have been mentioned twice? :/

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