Premise + Conclusion = Argument.
Now that you can find the conclusion, let's look at what the author is using to support it. That's the reasoning — the glue between premise and conclusion.
The anatomy of an argument:
Every LR argument has three parts:
- Premises — the evidence, data, or observations
- Conclusion — what the author wants you to believe
- Reasoning — the unstated connection between them
The reasoning is the hidden part. It's what makes the argument work (or not work). Your job is to find where the reasoning is doing heavy lifting — that's where assumptions live.
What reasoning actually is:
The LSAT doesn't write arguments where the premise perfectly proves the conclusion. If it did, every question would be easy. Instead, the reasoning requires a "leap" — an assumption the author makes without stating.
Example:
- Premise: "50% of students who used Method X scored above 170."
- Conclusion: "Method X is the best way to prepare for the LSAT."
The gap: Is "scored above 170" the same as "best preparation"? What about students who used Method X and scored below 170? What about other methods? The author's reasoning assumes the evidence covers all relevant factors.
Identifying the gap — where assumption begins:
Ask: What does the author need to be true for the conclusion to follow?
Whatever answer fills that gap is the assumption. And that's where most LR questions live — especially Assumption, Strengthen, and Weaken.
Weak vs. strong reasoning:
- Strong reasoning: The conclusion follows from the premises with minimal leaps. The gap is small or well-supported.
- Weak reasoning: The conclusion doesn't actually follow, or requires a large unstated assumption.
Weak reasoning often contains:
- Causal errors ("A happened before B, so A caused B")
- False dichotomies ("Either X or Y — and X is wrong, so Y must be right")
- Unrepresented evidence (ignoring data that contradicts the conclusion)
The instinct to build:
As you practice, you'll start to feel when the reasoning is making a leap. That feeling — the instinct — is your most valuable tool on the LSAT. Don't override it with overthinking.
The LSAT is simpler than you think. Find the gap. The right answer fills it.