Circular reasoning on the LSAT: when the premise is the conclusion

Circular reasoning is an argument whose support is the conclusion restated. It offers no evidence at all — it puts the claim on both sides of the therefore and hopes the rewording hides it.

On the LSAT it appears in the answer choices far more often than in the stimulus, which is the practical fact to know: it is a popular wrong answer, and choosing it correctly is worth more than recognizing it in the abstract.

What it looks like

The rewording is the whole disguise. "This policy is unjust, because it is not fair to those it affects" gives you unjust supported by unfair, which is the same claim in different clothes. "The witness is reliable because she reports accurately" does the same thing.

The test: strip the vocabulary and ask whether the premise says something the conclusion did not. If someone who doubted the conclusion would doubt the premise for exactly the same reason, the argument is circular.

How the test describes it

Answer choices name it in a few standard ways, and they are worth recognizing on sight:

• presupposes what it sets out to establish
• assumes the truth of the conclusion it is attempting to prove
• the conclusion is offered in support of a premise that is offered in support of the conclusion
• takes for granted the very point at issue

Why students over-select it

Because "this argument assumes too much" feels true of most flawed arguments, and circularity sounds like a description of that feeling. It is not. Nearly every flawed argument on the LSAT relies on an unstated assumption — that is what makes it flawed — and none of that is circularity.

The distinction is precise. A normal flawed argument offers evidence that does not get you all the way to the conclusion. A circular argument offers no evidence, because what it offers is the conclusion. If you can point at a premise that says something new, it is not circular, however weak that premise is.

That confusion is also why the choice is placed. When you see it and the argument had real evidence in it, that answer is there for people who found the argument unconvincing and reached for the most damning-sounding description.

Two near-relatives

• Assuming a disputed premise. The argument relies on something the opponent would reject, but which is genuinely a different claim from the conclusion. Flawed, not circular.
• A chain that eventually loops. Rare, and worth reading carefully — A supports B, B supports C, C supports A. Each step looks fine locally and the whole thing rests on nothing.