Logical Reasoning · Role of a Statement

PrepTest 135 · Section 4 · Question 21

Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.

Step 1 · Pre-Question Guidance · read this first

Question type

Role of a Statement

The one idea it tests

The first claim is the Boss, and the rest explains what it takes to prove a cause.

The basic logic

Check whether anything supports the claim in question. If what follows tells you why the claim must be true (by spelling out what you would need to know to pin down a cause), the claim is the conclusion and the rest is support.

Tiny words that decide it

“needs”
“unless”
“only”

Playground logic

Nadia's top bun: you need to watch the cat in many rooms to learn what makes him sneeze. Her patty: you cannot be sure the rug is to blame unless there are no rug-free rooms with sneezes and no rug rooms without them. The patty is the rule for proving a cause, and it holds up the Boss.

Step 2 · The kid story

The Sneezing Cat Mystery

Mr. Whiskers kept sneezing in the den. Marcus pointed at the shaggy rug. "Case closed. The rug did it." Nadia shook her head. "To find out what makes him sneeze, we have to watch him in a bunch of rooms, not just one. Here's why. We can't be sure the rug is the cause unless two things are true. First, he never sneezes in rooms without a rug. Second, he never skips sneezing in rooms that have one." Lulu drew a chart with four boxes. Priya nodded. "So the bunch-of-rooms idea is your main point, Nadia, and the rug rule is why." Marcus muttered, "I still think it's the rug." Mr. Whiskers sneezed on Marcus's shoe.

Step 3 · Try the model question

Nadia: To learn what makes Mr. Whiskers sneeze, we must watch him in several rooms. We cannot be sure the rug causes his sneezes unless he never sneezes in rooms without a rug and always sneezes in rooms with one.

The claim that Nadia must watch the cat in several rooms plays which role in her reasoning?

Step 4 · The courtroom tale

The Tomato Fertilizer Trial

A farmer sued a fertilizer company, saying its product made his tomatoes split. The company's expert spoke first. "Your Honor, to learn what causes splitting, you need records from many farms, not one. You cannot be sure the fertilizer is to blame unless no farm skipping it has split tomatoes, and no farm using it has whole ones." Mr. Whitfield, for the farmer, rose. "So your main claim is 'look at many farms,' and the rest is why." "Exactly." "Then we will bring many farms." The judge banged the gavel. "Recess. Go gather tomatoes."

Step 5 · Work the real question

Open PrepTest 135, Section 4, Question 21 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Find the statement named in the question and ask: does anything else in the argument support it? Look for a sentence that explains what would be required to prove a cause. If that sentence backs up the named claim, the claim is the conclusion. Pick the choice that calls it the claim being justified and names the right kind of support. Reject choices that invent problems, dilemmas, or examples the argument never offers.