Logical Reasoning · Weaken

PrepTest 136 · Section 2 · Question 5

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

Step 1 · Pre-Question Guidance · read this first

Question type

Weaken

The one idea it tests

An argument by comparison breaks when the two things differ on the very feature that drives the label.

The basic logic

The speaker rejects a label for X by pointing to Y: Y shares one feature with X, yet nobody gives Y the label. To pop it, show that Y lacks the other feature that earned X the label in the first place. Then the comparison is a Bad Comparison.

Tiny words that decide it

“yet”
“no one”
“but”

Playground logic

The family calls Biscuit a 'helper dog' because he rarely chews shoes and he brings in the newspaper. Marcus says that is silly: the neighbor's goat also rarely eats laundry, and no one calls it a helper. The pop: the goat never helps with anything, so the comparison skips the very reason Biscuit got his title.

Step 2 · The kid story

Biscuit, Helper Dog?

Grandpa calls Biscuit a 'helper dog.' Biscuit only chews a shoe once in a while, and every morning he carries in the newspaper. Marcus folds his arms. "That's silly. Look at Mrs. Lin's goat next door. It only eats laundry once in a while too, and nobody calls that goat a helper!" Kevin asks if goats like pineapple pizza. Priya puts down her juice box. "Marcus, Biscuit got his title for two reasons. He rarely makes trouble, and he does something useful. Your goat matches the first reason. Does the goat do anything useful?" Marcus thinks. "It mostly stares at fences." "Then your comparison falls apart," says Priya. "Of course nobody calls the goat a helper. It is missing the helping part." Biscuit drops the newspaper at Grandpa's feet, as if on cue.

Step 3 · Try the model question

Grandpa calls Biscuit a helper dog, since Biscuit rarely chews shoes and he fetches the newspaper. Marcus: That's a mistake. The goat next door rarely eats laundry too, yet no one calls that goat a helper.

Which, if true, would most damage Marcus's reasoning?

Step 4 · The courtroom tale

The Case of the Star Volunteer

A town names Rosa's bakery its 'Neighborhood Friend' because it rarely makes noise and gives free bread to the shelter. A rival lawyer objects. "Your Honor, the empty warehouse on Elm Street is quiet too, and nobody calls it a friend!" Aunt Rosa's lawyer, Mr. Whitfield, stands. "Does the warehouse give anything to anyone?" "Well, no. It is a warehouse." "Then the comparison misses the point. The title came from being quiet and generous. The warehouse is only quiet." The judge bangs the gavel. "The warehouse lacks the very trait that earned the honor. The comparison is popped."

Step 5 · Work the real question

Open PrepTest 136, Section 2, Question 5 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Spot that the conclusion rests on a comparison: something else shares one trait yet does not get the label. Go back and list every reason the original thing got the label. Then look for a choice showing the comparison case lacks one of those other reasons. That breaks the comparison. Choices that do not touch why the label was given cannot pop the comparison.