Logical Reasoning · Method of Argument

PrepTest 140 · Section 2 · Question 8

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

Step 1 · Pre-Question Guidance · read this first

Question type

Method of Argument

The one idea it tests

You can answer a comparison-based argument by pointing to a real difference between the two things being compared.

The basic logic

Speaker one says two things share a feature, so what is true of one is probably true of the other. Speaker two admits the shared feature but points to a difference that matters, then draws a different conclusion. Describe that move in abstract terms.

Tiny words that decide it

“probably”
“but”
“since”

Playground logic

Marcus reasons that the blue sled has the same runners as the red sled that flipped, so it will probably flip too. Lulu agrees about the runners but points out the sleds have different shapes, so they probably ride differently. She attacks the comparison by naming a difference.

Step 2 · The kid story

The Two Sleds

On the first snow day, the red sled flipped three times on the big hill. Grandpa put it away. Marcus pointed at the blue sled. 'That one has the very same runners as the red sled. So it'll probably flip too. Nobody ride it!' Lulu inspected the blue sled with her clipboard. 'You're right that the runners are the same. But the bodies are totally different. The red one is tall and narrow. The blue one is low and wide. So they probably won't ride the same way.' Grandpa chuckled. 'Smart girl. Same runners don't mean same sled.' Biscuit jumped onto the blue sled, slid all the way down, and did not flip once. Marcus declared the dog was a special case.

Step 3 · Try the model question

Marcus: The red sled flipped on the big hill. The blue sled has the same runners, so it will probably flip too. Lulu: The runners are the same, but the sleds' bodies are shaped very differently, so they probably ride differently.

Lulu responds to Marcus by

Step 4 · The courtroom tale

The Twin Bridges Case

A town sued to close the new footbridge. 'The old footbridge cracked last spring,' their lawyer said. 'The new one uses the same steel bolts. So it will probably crack too.' The builder's lawyer, Ms. Cho, stood up. 'Your Honor, the bolts are the same. But the old bridge was wood and the new one is stone, with a different design. So they will probably behave differently.' Judge Hart leaned back. 'Counsel, you compared two things. Ms. Cho showed they differ where it counts. The bridge stays open.'

Step 5 · Work the real question

Open PrepTest 140, Section 2, Question 8 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

First identify what the first speaker does: compares two things and carries a result from one to the other. Then ask what the second speaker does with that comparison. Does the second speaker accept the shared feature but point to a difference? Describe the move abstractly, then match it. Reject descriptions of moves the response never makes, such as attacking studies or invoking broad principles.