Logical Reasoning · Necessary Assumption

PrepTest 149 · Section 3 · Question 3

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

Step 1 · Pre-Question Guidance · read this first

Question type

Necessary Assumption

The one idea it tests

To show something is not always bad, you need at least one case where it happens and is fine.

The basic logic

The premise praises a group for good behavior. The conclusion says some action is not always wrong. The bridge: that group actually does that action. Pull the Plank: if none of them do it, the good behavior says nothing about the action.

Tiny words that decide it

“not always”
“many”
“some”

Playground logic

Priya's patty: many big reading buddies are kind to their little buddies. Her top bun: giving orders is not always unkind. The secret sauce is that some big buddies do give orders. Without that, their kindness proves nothing about orders.

Step 2 · The kid story

The Reading Buddy Puzzle

Frankie and Sharon were debating again. "Bossing people around is always unkind," said Frankie. Priya set down her juice box. "Lots of fifth graders in the reading buddy program are kind to their little buddies. So giving orders is not always unkind." Frankie squinted. "Wait. Do the big buddies even give orders?" Lulu checked her clipboard. "They say: sit here, turn the page, no licking the book." "Then that works," said Sharon. "But if they never gave orders," said Lulu, "being kind would not tell us anything about orders at all." Priya smiled. "Exactly. My argument needs that plank. Pull it, and the whole thing falls in the creek." Frankie sighed and admitted that "no licking the book" is a pretty kind order.

Step 3 · Try the model question

Priya: Many big buddies in the reading program treat their little buddies kindly. Therefore, giving someone orders is not always unkind.

Priya's argument depends on assuming which one of these?

Step 4 · The courtroom tale

The Case of the Bossy Crossing Guards

Your Honor, said Mr. Whitfield, the town says ordering people around is always rude. But many crossing guards treat walkers with great kindness. So ordering people is not always rude. The other lawyer stood. Objection. Do crossing guards give orders? Mr. Whitfield blinked, then held up a red stop sign. Every single morning. Stop. Wait. Go. The judge nodded. Without that, counsel, your kind crossing guards would be kind people doing nothing related to orders, and your argument would be a bridge with no middle. With it, the bridge holds. Motion granted.

Step 5 · Work the real question

Open PrepTest 149, Section 3, Question 3 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Write the premise and the conclusion side by side and notice that they talk about different things. Ask what must be true for the premise to say anything about the conclusion's subject. Usually it is the claim that the group in the premise actually does the action in the conclusion. Negate each choice: the right one, once negated, makes the argument fall apart. Reject choices that are stronger than needed.