Types of Fallacies

Formal – inference that fails because of poor logical form

affirming the consequent – (conditional) deductive fallacy: p→q, q, \ p. Example: “If she was a cadet, she’d be successful. She’s successful, so, she must’ve been a cadet.”

begging the question – using your conclusion as an implicit premise, or the truth of x is assumed within the original premise of x. Example: “I am not a liar.”

equivocation – using one word in more than one sense. Example: “Hot dogs are better than nothing. Nothing is better than steak. Therefore, hot dogs are better than steak.”

denying the antecedent – (conditional) deductive fallacy: p→q, ~p, \ ~ q. Example: “Give someone a gun, they might kill. Don’t give them guns, no killing.”

Material – the material of an argument – the premises – are faulty, making unwarranted claims and leading to unsound conclusions

ad hominem (to the person) – attacking the person rather than his/her argument; highlighting character to question a person’s judgment. Example: “My opponent is a…”

appeal to ignorance – arguing that a claim is true just because it hasn’t been shown to be false. Example: “There’s no intelligent life in the universe because no one has found any.”

complex question – answer makes a commitment to some other claim; two questions cluged together to where a single answer makes an unintended commitment, regardless of how a person answers (agreeing or disagreeing). Example: “You spend a lot of time online, do you enjoy all that pornography?”

composition/division – attributes from a small number are generalized to a broader group (composition)/ the parts of a system are assumed to all have characteristics of the whole system (Division). Examples: “Hydrogen and oxygen are gasses at room temp so H2O must be as well” (composition); and “You’re at USAFA, where you go to learn to fly, so you can fly” (Division).

false dilemma – reducing options under consideration to just two, often in sharp opposition; “either, or.” Example: “You’re with us or you’re with the terrorists.”

post hoc, ergo propter hoc – assuming causation merely on the basis of succession of time. Example: “I’m not feeling so good… must be the Mitches.”

straw man – caricaturing a view to make it easily refutable, or attacking the weakest point and declaring the entire argument flawed. Example: “They say character is so important, so show me this ‘character.'”

weak analogy - comparing X (in question) to Y (known, with desired property Z) to forge a connection – X is like Y which is Z-ful, therefore X is Z-ful. Example: “Four degrees are like dogs. They respond best to clear discipline.”

Diversions – push the discussion away from the subject and direct it toward other issues to make the audience forget or become unwilling to rejoin the topic. Successful diversions make it difficult to get back on track; counter by appealing to the audience’s sense of fair play.

humor – sarcasm and other forms of ridicule. Example: (Debating evolution) “Is the monkey on you grandmother or grandfather’s side?”

finger pointing – appeals to a sense of fairness. Effect is to (1) sidestep a grievance, (2) create sympathy, and (3) cause audience to measure one misdeed against another. Example: “People in glass houses shouldn’t throw stones.”

wicked alternative - comparing X in opposition to Y when Y is not the opposite of X. Example: “The British Health System doesn’t work, so we should reject “Obamacare.’”