Quest2Reason · Fallacies

35 fallacies on one page

What each mistake is, and a fair way to answer it. Free to print and share for class or study.

Changing the subject

Answering something other than the argument: the person, a distorted version, or a feeling.

Ad hominem: Attacking the person making an argument instead of the argument itself.; Answer it: “Even if that’s true about Dana, what’s wrong with the plan itself?”
Tu quoque: Dismissing a criticism because the critic does the same thing.; Answer it: “Fair, I should change that too. Now, is the point itself right?”
Genetic fallacy: Judging a claim by where it came from or why someone holds it, rather than by the evidence.; Answer it: “That’s a good reason to look closely. What do the figures show?”
Straw man: Replacing someone’s argument with a weaker or more extreme version, then knocking that down.; Answer it: “That isn’t what I said. My point was narrower: fewer cars in the center, not none.”
Red herring: Bringing in a different issue to pull attention away from the one being discussed.; Answer it: “That matters too, and we can come back to it. But first, about the budget…”
Appeal to emotion: Using feelings such as fear, pity or pride in place of reasons.; Answer it: “I do care about that. What makes this option the one that helps?”
Appeal to consequences: Deciding whether something is true by whether you would like the result.; Answer it: “It would be expensive, I agree. But is the bridge safe or not?”

Leaning on the wrong support

Treating popularity, fame, nature, habit or silence as if it were evidence.

Bandwagon: Treating a claim as true because many people believe it.; Answer it: “What is the evidence that convinced them?”
Appeal to authority: Accepting a claim because someone famous or important said it, outside their expertise or without reasons.; Answer it: “What do people who study this say, and on what evidence?”
Appeal to nature: Assuming that what is natural is good or safe, and what is artificial is bad.; Answer it: “Natural or not, what does the evidence say it does?”
Appeal to tradition: Treating a practice as right because it is old or customary.; Answer it: “What was it for, and does that reason still hold?”
Appeal to ignorance: Claiming something is true because it has not been proved false, or false because it has not been proved true.; Answer it: “You’re the one making the claim. What’s the evidence for it?”
Sunk cost fallacy: Continuing something because of what you have already spent on it, rather than what lies ahead.; Answer it: “If we were starting fresh today, would we choose this?”

Rigging the question

Building the answer into the setup, or changing the rules once the test is under way.

False dilemma: Presenting two options as the only ones when there are more.; Answer it: “Are those really the only two options? What about…?”
Slippery slope: Claiming one small step will inevitably lead to a chain of extreme results, without showing why.; Answer it: “Why would the first step lead to the second? Couldn’t we stop there?”
Begging the question: Using the conclusion, in other words, as one of the reasons for it.; Answer it: “That reason only works if I already accept what you’re trying to show. Is there independent support?”
Loaded question: Asking a question that smuggles in an assumption, so any direct answer accepts it.; Answer it: “That assumes I was wasting money, which I don’t accept. Here’s what I actually spend.”
Moving the goalposts: Changing what counts as evidence after the original test has been met.; Answer it: “Before I find more, what would actually change your mind?”
No true Scotsman: Protecting a generalization by redefining the group to exclude any counterexample.; Answer it: “What would count as a real fan, decided before we look at the cases?”
Motte and bailey: Advancing a bold claim, retreating to a modest one when challenged, then advancing again.; Answer it: “I agree with the modest version. Are you still claiming the strong one? That needs its own evidence.”
Special pleading: Applying a rule to others while claiming an exception for yourself without a good reason.; Answer it: “What makes this case different in a way that matters for the rule?”

Slippery words and shapes

Arguments that look valid because of a shifting word or a borrowed shape.

Equivocation: Shifting between two meanings of the same word partway through an argument.; Answer it: “In which sense do you mean that word? It seems to change between your premises.”
Composition and division: Assuming what is true of the parts is true of the whole, or what is true of the whole is true of each part.; Answer it: “Does that property actually pass from the members to the group?”
Affirming the consequent: Reasoning from “if A then B” and “B” to “A”, which does not follow.; Answer it: “What else could explain B, apart from A?”
Denying the antecedent: Reasoning from “if A then B” and “not A” to “not B”, which does not follow.; Answer it: “Is A the only way to get B?”
Weak analogy: Arguing that two things are alike in one way because they are alike in others, when the differences matter.; Answer it: “They’re alike in some ways, but they differ in the one that matters here: …”

Bad evidence

Mistakes about causes, samples and chances: the story outruns the numbers.

Post hoc: Assuming that because one thing happened after another, the first caused the second.; Answer it: “Would it have happened anyway? What else changed at the same time?”
Correlation is not causation: Concluding that because two things go together, one causes the other.; Answer it: “Interesting link. What else might explain both?”
Hasty generalization: Drawing a general conclusion from too few or untypical cases.; Answer it: “That shows it can happen. How often does it happen?”
Cherry-picking: Showing only the evidence that supports a claim and leaving out the rest.; Answer it: “Those cases are real. What do all the cases look like together?”
Texas sharpshooter: Finding a pattern in random data after the fact, then treating it as meaningful.; Answer it: “Would we have predicted that before looking? Does it hold up with new data?”
Survivorship bias: Drawing conclusions from the cases that made it through a filter, and forgetting the ones that did not.; Answer it: “How many did the same and didn’t make it?”
Gambler’s fallacy: Believing that a random event is more or less likely because of what happened just before.; Answer it: “Does the next spin depend on the last one?”
Base rate fallacy: Ignoring how common something is in general when judging a particular case.; Answer it: “Before the details, how common is this in the first place?”
Conjunction fallacy: Judging a detailed story as more likely than a simpler one it contains.; Answer it: “Each detail has to be true as well. Does adding it really make the story likelier?”

From quest2reason.com/, where each fallacy has its own page with an example and how to spot it, and a free daily climb through philosophy and clear thinking.