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Logical Reasoning

The Most Important Logical Reasoning Habit

What's the most important habit that sets apart people who consistently ace LSAT logical reasoning from those who struggle?

They understand conclusions precisely. 🎯

In my experience as a tutor, a huge portion of students’ mistakes in logical reasoning result from a “blurry” picture of the conclusion. Stated differently, these mistakes stem from overlooking small, but important distinctions between what the conclusion actually says and what it doesn’t. 

Sometimes the issue is that the student doesn't identify conclusions accurately. If you have this problem, try doing more untimed sections, cover up the answers, and practice labeling the different parts of each argument you encounter. 

Sometimes the issue is that a student isn't aware of what a word really means. If this is your problem, keep track of words you don't know and look up the definitions. (By the way, real lawyering actually does involve looking up definitions of words and definitions of words in those definitions.)

But more commonly, the problem is the student doesn't hold themselves to a high enough standard. They tell themselves that they know what the conclusion is “basically” saying, and what the argument is “about” and then rush to the answer choices. The problem is (1) they don't read slowly enough to notice the precise meaning of the conclusion or (2) don't treat attaining a precise understanding as a non-negotiable requirement of attempting the question. 

Did the author conclude that the vacuum was “effective” or “the most effective”? If she said it was effective, then pointing out that it's not as good as the competing brand is irrelevant ❌ - it can still be effective even if it's not the best. On the other hand, if she said it was the most effective, then a comparison to another brand’s effectiveness matters ✅.

Did the author conclude that the vacuum was “the most effective” or that we “should buy it”? If she said only that it was the most effective, then pointing out that it’s the most expensive or that it’s more powerful than anyone actually needs would be irrelevant ❌ - those factors don’t relate to how good the vacuum is at cleaning things up. But if she concluded that we should buy it, those other qualities start to become relevant ✅, because they may cut against the decision to buy it.

Did the author conclude that we “should buy” the vacuum or that we “should buy it if we care about having a clean floor”? If she said the former, then it might weaken the argument to learn that we don’t care about how clean the floor is ✅. But if she said the latter, then it doesn’t matter whether we actually care about the cleanness of the floor, because her conclusion is about the hypothetical situation in which we do care ❌. 

So, if you want to ace the LR section, then on argument-based questions:

  • You must identify conclusions accurately, and
  • Read them slowly enough to understand exactly what they're saying and what they're not saying.

🚩 Real LSAT Example 🚩

One of my favorite LSAT questions to demonstrate the importance of precisely understanding the conclusion is PT41, LR2, #17 (Autism diagnosis test). Go to your LawHub and try this problem first if you don’t want spoilers. I’d be happy to copy/paste the problem here, but the LSAC puts out hits on people who violate their copyright. 

The conclusion of the argument in this question is

“Autistic children can therefore now benefit much earlier in life from treatments already available.”

The less precise among us often interpret this conclusion as something like “We should start using the new test” or “It’s OK to use the new test.” And because of this interpretation, they are tempted by answer choice (D). "Huh," they think. 🤔 "If we're going to use this test, don't we need to know that the wrongly identified kids won't be hurt by it?"

The argument’s conclusion, however, is purely a descriptive claim about the world: autistic kids can benefit earlier from treatments. The conclusion doesn't actually advocate or condone the use of the test. 

So, what if it turns out that by using the test, the non-autistic kids falsely identified as autistic will be harmed by unnecessary courses of treatment? What if they’re condemned to lives of excruciating pain and misery? It may seem callous, but…we just don't care.

Perhaps that would suggest we might want to be careful about using this test…but that’s not relevant to the author’s conclusion. The non-autistic kids might as well not even exist as far as the conclusion is concerned. Even if they end up suffering adverse effects, that has nothing to do with whether autistic children would still benefit from being diagnosed earlier as a result of the new test. So (D) is not a necessary assumption of the argument.

What's the takeaway? If you're not doing as well in LR as you'd like, keep this in mind:

We don't care about those kids.

We don't care about those kids.

We don't care about those kids.

Let that be a mantra you recite before every logical reasoning section as a reminder of how ruthlessly precise you need to be on this test when it comes to an argument's conclusion.

Future LSAT Reading Comp Passages

This section of the post collects interesting online articles that you might see edited down to an actual LSAT RC passage in the distant future. Read these recommendations every week and I can guarantee that your RC score will improve or you'll learn something interesting about the world, or both.

🌳  Forests Emerge as a Major Overlooked Climate Factor | Quanta Magazine

🔫  "Lineal Descendant" Analysis in Second Amendment Litigation | Harvard Law Review Blog

⚔️  A history of disruption, from fringe ideas to social change | Aeon Essays

👞  How Aurore Dudevant put on men’s boots to become George Sand | Aeon Essays