Bad Arguments

An argument is when you express a conclusion with some justification. A bad argument is when the justification doesn't support the conclusion.

Learn bad arguments so that you recognize them, avoid using them, and aren't persuaded by them.

The following are ordered (approximately) from most-common to least-common. Their names are intended to evoke their meanings and be easy to remember. An argument can be multiple kinds of bad. Most bad arguments appeal to biases.

When a bad argument is right more often than wrong, it can be transformed into a good argument. Re-express the conclusion to accurately reflect how often it's actually correct.

Cherry-picking (aka half-truth) — You select evidence that supports your conclusion and ignore or discount other relevant evidence.
Digressing — You avoid the argument by changing the subject, or diverting attention to someone or something else that's irrelevant.
Straw man — You distort or misrepresent their argument to make it easier to attack.
Character attack (aka ad hominem) — You attack the person instead of their argument. This includes name-calling, labeling, and inferring sinister motivations. You're guilty of this when someone criticizes you and you critize them back instead of addressing their criticism.
Guilt by association — You link one thing with an irrelevant other thing in order to make it look better or worse. One form of this is the genetic fallacy, where you judge something by where it comes from or who it comes from, rather than by its own attributes.
Over-generalizing — You claim that something is broadly true about a category based on just one instance, or a few instances, which are not enough instances to make confident claims about the category. A common case is using your personal experience or anecdotal evidence to support generalizations.
Over-specifying — You claim that something that's true of a group is true of a member, when that's not necessarily so. Just because the average height of humans is 5'4", doesn't mean Susan is 5'4". Just because most people have 10 fingers doesn't mean Joe has 10 fingers.
Appeal to ideology — By ideology, we mean "a set of abstract prescriptive beliefs that embodies a purified virtue." This is where you judge based on the virtues or vices of an ideology which you see at stake in an abstract issue. This is a bad argument because: it over-simplifies issues and over-generalizes solutions; it ignores the details and context of particular cases; it ignores expirical outcomes; and it may ignore other good values that need to be balanced. Real-world issues benefit from: balancing or prioritizing multiple values; informing your judgement by empirical outcomes; admitting exceptions and complexity; and judging case-by-case instead of pre-deciding in general. Any virtue taken to an extreme becomes a vice.
Loaded question — You ask a question that makes an assumption or implication so that no matter what the other person answers, they seem guilty.
Appeal to popularity (aka bandwagon) — "Everyone thinks so, therefore it's true."
Appeal to tradition — "It's tradition, therefore it's true." Just because it's ancient or socially acceptable doesn't make it good or true.
Appeal to authority — "This authority thinks so, therefore it's true." Not necessarily. Authorities can be cherry-picked, biased, and just plain wrong. This argument is particularly bad when the authority is irrelevant.
Appeal to consequences — "We like the conclusion, so it's true", or "We don't like the conclusion, so it's false."
Appeal to emotion — You recruit support for your conclusion by getting your audience to react with strong emotions — like fear, envy, hatred, pity — rather than using rational justification.
Appeal to ignorance — "You can't (or won't) verify my claims, so I'm right."
Appeal to familiarity — "I'm familiar with this, therefore other things are worse." The devil you know is better than the devil you don't.
Appeal to nature — "It occurs naturally, therefore it's good." Not necessarily.
False dilemma (aka false dichotomy, black and white) — You make it seem like the only options are a small set, where one option is obvious. This is an over-simplification and a mischaracterization of the actual possibilities.
Necessary but not sufficient (aka affirming the consequent) — Let's say there's a situation where "when A is true, B is necessarily true", such as "If you fall into a volcano, you'll die." However, you claim (erroneously) that "B is true, therefore A is true", such as "Joe died, therefore he fell into a volcano." Another example: "Joe is a male, and every brother is male, therefore Joe is a brother." Not necessarily.
False compromise — You claim that the truth must be in between two extremes, when in fact the truth is (or could be) one of the extremes. For example, if one claim is "vaccinations cause autism" and another claim is "vaccinations do not cause autism" and you conclude that "vaccinations must sometimes cause autism."
Correlation does not imply causation (aka false cause, post hoc) — "These two things happened in sequence, therefore the first one caused the second". If you flip a coin 10 times and it's heads each time, that doesn't change the probability of the next flip.
Illogical (aka false logic, non-sequitur) — You claim that a conclusion follows from the premises, when it doesn't. This is when a transition from one proposition to the next is an error. For example, "It's illegal, therefore it's unethical". That just doesn't follow.
Jumping to conclusions — You pick one interpretation out of many possibles ones. Example: conspiracy theories.
False burden of proof — You make a claim and assert that it's true unless your opponent can disprove it. Instead, the burden of proof is actually on the person making the claim.
Equivocating — You claim an unintended meaning of ambiguous language to support your conclusion. For example, you tell the judge that you interpreted the "Fine for parking here" sign as "It's okay to park here" instead of "You'll get a fine if you park here".
Slippery slope — You claim that one thing will inevitably lead to a domino effect of more things that are bad, when in fact it's not inevitable.
The righteous agree (aka appeal to virtue, agree or you're a bad person) — You couch your conclusion so that agreeing with you makes them seem virtuous and disagreeing with you makes them seem disreputable. "It embodies values we hold dear, therefore it's true", or "It evokes values we're against, therefore it's false." This is often a form of psychological or social coersion to comply with a social norm.
Circular reasoning (aka begging the question) — "My conclusion is true, therefore my conclusion is true".
False exception (aka special pleading) — You claim something is an exception, when it's really not. If someone shows your claim to be wrong, you change the criteria for what counts. Example: No true Scotsman.
Just a coincidence — "This event is unlikely, therefore it's meaningful." A form of this is seeing patterns in noise.
Argument from bewilderment — "I don't understand it, therefore it's not true." For example: "I don't understand how we could have evolved from fish, so it can't be true."
Fallacy fallacy — "They made a bad argument, therefore their conclusion is wrong" or "... therefore the opposite is true". Not necessarily. Their conclusion might still be right. Their bad argument doesn't mean the opposite is true. One mistake in an argument doesn't mean other justifications are wrong, or that the arguer is wrong about other things.
False doubt — When you attempt to discredit a conclusion by introducing doubt in the form of plausible but thusfar unjustified possibilities. For example, the cigarette industry tried to discredit evidence that smoking causes cancer by promoting cherry-picked doctors and citing (and funding) bad studies.