Circular Reasoning on the LSAT: When the Premise Is Just the Conclusion in Disguise
Some LSAT flaws are loud. Others are so quiet that you read right past them because the argument sounds finished. Circular reasoning belongs in the second group, and it is worth learning precisely because it feels like nothing is wrong.
Here is the idea in one line: an argument is circular when the premise and the conclusion say the same thing in different words. The author is supposed to give you a reason to believe the conclusion. Instead, the author hands you the conclusion again, dressed up as support. Logicians call this begging the question.
Start with a sentence that sounds convincing: “This novel is the best of the year because no other novel published this year is as good.” Read it slowly. “Best of the year” and “no other novel is as good” are the same claim. The word “because” is doing nothing. There is no new fact in the premise, only a rephrasing of the conclusion.
Now compare a version that actually works: “This novel is the best of the year because it won three major literary prizes that no other novel won.” The premise is now a separate fact. You could check it. Someone who doubted the conclusion might still accept the premise and then be moved. That is what real support looks like.
That last observation is the fastest test I know. Ask yourself whether someone who doubts the conclusion would accept the premise. If accepting the premise already requires accepting the conclusion, the argument is circular. A skeptic about the “best novel” claim would reject “no other novel is as good” for exactly the same reason they reject the conclusion, because it is the conclusion.
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A second test is the swap. Write the premise and the conclusion side by side, and imagine trading them. If the argument reads the same after the trade, you are looking at one claim wearing two outfits.
Why does this matter on test day? Because the LSAT almost never labels the flaw for you. The question stem asks something like “The reasoning in the argument is flawed because it,” and the answer choices describe the problem in abstract language. For circularity, you will see phrasings such as “presupposes what it sets out to prove” or “the conclusion is among the premises.” If you have not practiced spotting the pattern, those choices read like filler. If you have, one of them lights up immediately.
There is a trap on the other side too. Not every argument that repeats itself is circular. An author can restate a point for emphasis and still offer a real reason elsewhere. Before you commit, check whether any premise is independent of the conclusion. If at least one premise supplies a new fact, the argument may have other problems, but it is not circular in the LSAT sense. Circularity requires that the support collapses into the conclusion.
Here is how I would drill this. Take ten flawed arguments from any practice set. For each one, underline the conclusion, then underline the premise, and write one sentence answering: “What does the premise tell me that the conclusion did not already say?” If your honest answer is “nothing,” you have found a circle. If your answer is “a specific fact,” move on and look for a different flaw. After a week of this, the pattern starts to jump out at you without the underlining.
Circular reasoning is one of the rarer named flaws, so you will not see it every section. But when it does appear, it is some of the cheapest points on the test, because the detection step is so mechanical. Rare and easy is a good combination to invest in.
If you want to keep going, pair this with the equivocation flaw and the work of separating premises from conclusions. They train the same habit: refusing to let a sentence count as support until you have asked what it actually adds.
I originally published the complete version of this framework on Verbloom.
