Kinds of Argument: Definition, Evaluation, Causal, and Proposal

Before you can judge whether an argument works, you need to know what job it's actually doing. A definition argument settles where a category's boundary falls—does chess count as a sport, does a tomato count as a vegetable. An evaluation argument applies a standard to something already defined—granted that chess is a sport, was that particular match well played. A causal argument claims one thing produced another, and it owes a reader a mechanism, some account of how X actually led to Y, not just that they happened together. A proposal argues for a course of action, and it owes a reader a case that the plan is worth its cost compared to the alternatives.

Each type fails in its own specific way. A definition argument fails if its criteria are arbitrary or don't match how the word is actually used. A causal argument fails if it ignores rival explanations—maybe the vacancies rose because of a recession, not the parking levy. A proposal fails if it shows the problem is real but never proves the specific plan is the best fix for the money. Knowing which kind of argument you're facing tells you exactly where to push.

This sorting connects directly to spotting unstated assumptions. Once you know an argument is causal, the missing premise you're hunting for is almost always 'no other cause explains this better.' Once you know it's a proposal, the missing premise is usually 'this plan's benefits outweigh its costs relative to other options.' The structure tells you what block is missing before you even look closely.