Logical Fallacies
Spot a straw man, a false dilemma or a post hoc argument from a single line of dialogue.
Bad arguments tend to fall into a small number of patterns. This deck gives you an argument in a sentence or two and asks which fallacy it commits, with four names to choose from. The answer explains the pattern in plain words, so it is recognisable the next time it shows up in a meeting, a comment thread or a news segment.
All 24 cards
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“Why listen to her views on the budget? She’s been divorced twice.”
Ad hominem
Attacking the person making the argument instead of the argument.
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“You want to cut the defence budget? So you want to leave the country defenceless.”
Straw man
Distorting someone’s position into a weaker one, then knocking that down.
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“Either you support this law or you don’t care about children.”
False dilemma
Presenting two options as the only ones when there are more.
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“If we let students redo one test, soon nobody will study at all.”
Slippery slope
Claiming one step will lead to an extreme outcome, without showing why.
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“A famous actor says this diet works, so it must.”
Appeal to authority
Treating a claim as true because someone with status, often outside their field, said it.
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“Millions of people use it, so it must be good.”
Appeal to popularity
Treating a claim as true because many people believe it.
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“The book is trustworthy because it says it is.”
Circular reasoning
Using the conclusion as one of the reasons for it.
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“My two neighbours from that city were rude, so people there are rude.”
Hasty generalization
Drawing a broad conclusion from too few examples.
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“I wore my lucky socks and we won, so the socks helped.”
Post hoc
Assuming that because one thing followed another, the first caused the second.
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“Why worry about the factory’s pollution when there are so many unemployed people?”
Red herring
Bringing in an unrelated issue to pull attention away from the real one.
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“You say I should quit smoking, but you used to smoke.”
Tu quoque
Dismissing a criticism because the critic is guilty of it too (“whataboutism”).
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“It’s herbal, so it can’t hurt you.”
Appeal to nature
Assuming something is good because it’s natural, or bad because it isn’t.
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“No real fan would leave before the end.” “But I did.” “Then you’re not a real fan.”
No true Scotsman
Changing a definition to shut out a counterexample.
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“Prove that ghosts don’t exist.”
Burden of proof
Expecting others to disprove a claim instead of supporting it yourself.
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Pointing to the three towns where a product sold well and ignoring the dozens where it didn’t.
Texas sharpshooter
Picking out the data that fits a pattern after the fact and ignoring the rest.
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“Have you stopped wasting company money?”
Loaded question
Asking a question that assumes something unproven, so any answer seems to admit it.
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“Think of how sad your mother would be if you didn’t buy this policy.”
Appeal to emotion
Moving people with feelings instead of reasons.
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“One side says the earth is round, the other flat, so the truth is somewhere in between.”
Middle ground
Assuming a compromise between two positions must be correct.
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“That idea came from a tabloid, so it’s false.”
Genetic fallacy
Judging a claim by where it came from rather than on its merits.
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“My grandfather smoked every day and lived to 95, so smoking isn’t that bad.”
Anecdotal evidence
Using a personal story or isolated case in place of real evidence.
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“Nobody has proved it’s unsafe, so it’s safe.”
Appeal to ignorance
Claiming something is true because it hasn’t been proved false, or the reverse.
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“A feather is light. What is light cannot be dark. So a feather cannot be dark.”
Equivocation
Switching between two meanings of a word partway through an argument.
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“Every player on the team is excellent, so the team must be excellent.”
Composition
Assuming what is true of the parts must be true of the whole.
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“I can’t see how evolution could produce an eye, so it can’t be true.”
Personal incredulity
Rejecting something because you find it hard to understand.