A premise is relevant if it provides genuine evidence for the conclusion. Relevance fallacies include ad hominem (attacking the arguer rather than the argument), inappropriate appeals to emotion or authority, or distracting from the real issue. True premises don't guarantee relevance to the conclusion.
Ask: 'Does this premise actually address the conclusion being argued?' For instance, 'The CEO says the product is good because she's intelligent' doesn't show the product is good. Identify what issue is being debated, then check if premises address it.
From your study of argument structure — premises, conclusions, and the inferential connection between them — you know that a good argument provides reasons *for* its conclusion. But "providing a reason" is not just a formal requirement; it is a substantive one. A premise can be entirely true and yet provide zero support for a particular conclusion. Relevance is the property a premise has when it actually bears on the question being argued.
The clearest way to see this is through the ad hominem pattern. Suppose someone argues: "You should not trust the climate data because the scientist who collected it once cheated on a parking ticket." Even if the cheating claim is true, it doesn't address the quality of the data, the methodology of collection, or the reliability of the instruments. The premise is *about the arguer*, not about the argument itself. The conclusion concerns the data; the premise concerns a person's character. There is no inferential bridge between the two. This is why attacking the person rather than the reasoning is a fallacy of relevance — the premise is pointed in the wrong direction.
A similar structure underlies appeals to inappropriate authority: "Professor X is brilliant, so we should accept her claim about vaccine safety." Brilliance is a general property; relevance to a specific domain is what matters for testimony. If Professor X is a philosopher rather than an immunologist, her general intelligence does not make her testimony evidence for a medical claim. Relevance requires that the premise supply reasons *specifically connected* to the type of conclusion being drawn. The diagnostic question is: would this premise still support the conclusion if we held everything else fixed? If the answer is no — if the connection depends on an unexamined assumption — the premise may be irrelevant.
The key skill is clearly isolating the question at issue before evaluating premises. Every argument is made in a context where certain things are in dispute and others are not. A premise is relevant if it provides evidence for or against *that specific dispute*, not just something in the neighborhood. When a premise shifts focus — to the arguer's motives, to emotional associations, to unrelated consequences — it exploits the fact that such shifts can feel like engagement while actually dodging the question. Developing sensitivity to relevance means asking, at each premise: "Does this address what we're actually debating, or does it change the subject?"
Topics in reflective domains aren't scored by quiz answers. Read, reflect, and mark when you've thought it through.