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So remember a long time ago when I posted a complete list of logical fallacies? Wasn’t that great? Well, I was thinking, it’s high time I posted these again.  Here they are, for your viewing pleasure—a list of the ways that we tend to screw ourselves over when we argue, debate, write, or form opinions.  These are for my education as much as yours—we all commit these errors from time to time.  But as with all things unconscious, giving them names and knowing they exist helps immensely to make you better at not doing them, and plus it feels really good to shout Latin across the room at people who are being annoyingly wrong and stuff.  SO here is a revised and reposted version of THE LIST OF LOGICAL FALLACIES.

Oh, and if you see anything that looks like it needs clarification or just straight-up seems wrong, let me know! I’m all for dialectic and dialogue and stuff!



  • Argumentum ad baculum: Appeal to force. More literally, “argument by stick.” “Do you know what the chain of command is? It’s the chain I beat you with until you understand who’s in ruttin’ command!”
  • Argumentum ad misericordiam: Appeal to pity.  Also known as “The Smeagol Fallacy.” 
  • Argumentum ad populum: Argument by the people. In other words, argument by social pressure. The people are in favor of X, therefore X is good. “Whenever people agree with me I always feel I must be wrong.”
    • (ad populum) Celebrity endorsement: “Kanye West is in favor of new Bay-B-Lite, the delicious energy drink made from babies! It can therefore only be a good idea!”
    • (ad populum) Snobbery: Also known as the Grey Poupon Fallacy*.
  • Ad hominem: Argument to the man. Making the debate about the other person rather than about the argument itself**.  “You’d basically have to be a husk of a person to hate unicorns.”
    • Ad hominem abusive: Cicero said it best. “When you have no basis for an argument, abuse the plaintiff.”
    • Ad hominem circumstantial: someone is in circumstances such that they are disposed to take a particular position.  But just because the person arguing to legalize same-sex marriage is gay, doesn’t mean their argument is any less valid (assuming it’s valid in the first place). 
    • Ad hominemTu quoque”  (“You too”): Pointing out that your opponent’s rants in favor of radical veganism have been interrupted frequently by bites he’s taken from the wad of beef jerky in his hand.
  • Fallacy of Accident (a dicto simpliciter ad dictum secundum quid) (destroying the exception): Cutting people with knives is illegal. Surgeons cut people with knives. Surgeons are criminals. What went wrong here? We ignored an important exception to the rule about cutting people with knives.  
  • Straw Man: Arguing with a position that the other person didn’t take. For an example, review the comments section of any Youtube video.
  • Ignoratio elenchi: Missing the point entirely.  Usually the key marker for this one is that the conclusion comes completely out of nowhere.
    • (Ignoratio elenchi) Red Herring Fallacy: Deliberately missing the point to lead the discussion astray.  Can easily segue into a straw man.
  • Argumentum ad vericundiam: An appeal to some authority that happens to be completely unqualified for the situation at hand. Example: bringing Doctor Phil into any discussion of psychology***.  Exception: Aristotle is always relevant.
  • Argumentum ad ignorantiam: The appeal to ignorance.  The absence of evidence is taken to be evidence of absence.  “I’ve never seen Switzerland—I don’t think it exists. It’s a government conspiracy.  A comforting myth, like Santa Claus or Canada.”
  • Converse Fallacy of Accident (a dicto secundum quid ad dictum simpliciter): A hasty generalization. “Dobby the House-Elf wanted to be free of his master! The same must hold true for ALL HOUSE-ELVES!”****
  • False Cause (Non causa pro causa) (“Non-cause for cause”): A false causal claim.  Examples below.
    • (False Cause) Post hoc, ergo propter hoc (“After this, therefore because of this”): Causal claim about a vaguely correlated fact. “The number of true swashbuckling pirates decreased after global temperatures increased.  Thus, GLOBAL WARMING KILLS PIRATES.” 
    • (False Cause) Cum hoc ergo propter hoc (“with this, therefore because of this”): “I wore my yellow Argyle-Paisley socks to school today, and I got 100% on everything I did! I’m gonna wear these things all week!”
    • (False Cause) Oversimplified Cause: Pulling out one specific cause for a complex event. The blame game applies. “You know whose fault it was that the hurricane destroyed the train depot? STEVE. He didn’t lock the doors when he left on Friday! GOD DAMN IT, STEVE.”
    • (False Cause) Gambler’s Fallacy: “I’m due for a big win any time now!” Actually, that’s not how probability works: You’re just as likely to get heads as tails regardless of how many heads come in a row.
  • Slippery Slope: A leads to B, B leads to C, C leads to D and so on, until one finally claims that A leads to Z. While this is how arguments actually work, slippery slope fallacies occur when this is not done properly—when, for example, there is nothing that supports the link between C and D.  You see this in politics all the time–at first there are some good steps drawn out about cost of education, some less grounded steps follow, and the next thing you know the gay communist Mexican mafia is running our schools and teaching Meth 100 in first period.  
  • Weak Analogy/False Analogy. The term “false analogy” was coined by none other than JOHN GODDAMN STUART MILL. The example is paraphrased from his. Arguing by analogy is how we reason normally. Unfortunately, in this case we’ve just done it wrong. “Person X is lazy. I don’t know their sibling, Person Y, but I can only assume that they are lazy too.”
  • Petitio principii (Assuming the start; begging the question): A statement is assumed to be true without further proof than the statement itself. E.g.; (in simplified form) “I think he is unattractive because he is ugly.”  You’ll see this a lot in those stupid debates between religion and science; “I know the Bible quote is true because the Bible says it’s true, and the Bible, being the word of God, is never wrong.” Or “This objective fact is absolutely true, because it is tested using the scientific method, and the scientific method is based in objective fact.”
  • Complex Question: A loaded question. “Good morning, Dave! Have you stopped beating your kids yet?”
  • False Dichotomy: Some issue is presented as having only two possibilities. “Mom, either we go and get ice cream, or THE COMMUNISTS WIN. You’re not a communist, are you, mom? I didn’t think so.” In actuality there are more options: they could not get ice cream, the communists could in fact lose anyway, or they could get frozen yogurt and promote gastrointestinal health while beating back the Red Scourge.
  • Suppressed Evidence: ‘Cherry picking;’ taking only the evidence that supports your case, suppressing information that could be sufficient to disprove your point without further ado. For further details see the Global Warming “debate.”
  • Fallacy of Equivocation: Playing with the meanings of a word, using it in a different sense from previously. This can be as simple as “Something must be done.  This is something. Therefore, this must be done,” or as complex as making a subtle change to the connotative meanings of ‘environmentally sound.’
  • Amphiboly: A fallacy resulting from an ambiguous or lazy grammatical structure.  Often quite silly. Simple example: “No food is better than our food.”  To interpret this as meaning “our food sucks” is to commit the fallacy of amphiboly. 
  • Fallacy of Division: Assuming incorrectly that something true of a thing must be true of all its parts. “This chair is green. All its component atoms must be green as well.” Similar to the hasty generalization, but don’t assume they’re the same.
  • Fallacy of Composition: Assuming incorrectly that something true of all the components is true of their sum. “All these atoms are invisible.  The chair they form must also be invisible.”

*Although Grey Poupon mustard is indeed delicious, the method by which they sell it is an ad populum appeal to elitism.  It is marketed as “the gentleman’s mustard,” which (a) sounds like a euphemism and (b) has no bearing on its actual quality.

**While the nature, actions, and background of the other speaker may have some bearing on why they are making a given argument, they have no effect whatsoever on the actual validity of the statement.  When Dick Cheney lectures about the huge losses of life in the Middle East, he may be a horrible hypocrite, but that doesn’t affect the facts of what he is actually saying.  A key portion of logic is the ability to pull the irrelevant away and focus only on the argument.


****I am actually an outspoken activist in the matter of House-Elf civil rights, and a proud member of S.P.E.W.  One of the first Slytherin members, as it happens.

This has been another overly wordy blog post, and I apologize.  Have a spiffy day.


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