Logical Reasoning · Flaw

PrepTest 142 · Section 2 · Question 18

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

Step 1 · Pre-Question Guidance · read this first

Question type

Flaw

The one idea it tests

An argument picks one explanation for a lasting result while a second, simpler explanation is sitting right there, untouched.

The basic logic

Find the result that kept happening after the test ended. Ask: what else, besides the author's favorite story, could make it keep happening? If the test itself might have done lasting harm, the argument never ruled that out.

Tiny words that decide it

“consequently”
“once”
“ceases”
“continued”

Playground logic

Marcus sees Tommy keep playing clunky after the mittens come off and decides Tommy stopped listening to himself. The patty is real, but the top bun ignores a second door: the mittens may have left his fingers stiff. That is an unchecked alternative cause, a cousin of the Rooster.

Step 2 · The kid story

The Mitten Piano Mystery

For three weeks, Tommy practiced piano wearing Grandpa's thick winter mittens. Lulu wrote it all on her clipboard. With mittens on, every song came out loud and clunky. Then the mittens came off. Tommy sat down, cracked his knuckles, and played... loud and clunky. "Case closed," said Marcus, tapping his detective hat. "Once Tommy learns a way to play, he stops listening to the sound. His ears have retired." Priya sipped her juice box. "Or," she said, "three weeks inside giant mittens made his fingers stiff. Stiff fingers clunk no matter what your ears are doing." Marcus frowned. "I did not check his fingers." "Nope," said Lulu, underlining it twice. "You checked your favorite answer." Tommy wiggled his fingers. They creaked a little.

Step 3 · Try the model question

Tommy practiced piano in thick mittens for three weeks and played clunky the whole time. After the mittens were removed, he still played clunky. So once Tommy settles on a way of playing, he stops using his ears to guide his fingers.

Marcus's reasoning is open to which criticism?

Step 4 · The courtroom tale

The Case of the Squeaky Bicycle

Mr. Whitfield snapped his suspenders. "Your Honor, my client's nephew rode with a bent wheel for a month. The wheel was fixed, yet the bike still pulls left. The other side says the boy has simply learned to steer crooked." Judge Moss raised an eyebrow. "And your answer?" "The bent wheel rubbed against the frame all month. Maybe the frame itself got bent. Nobody looked." The opposing lawyer shuffled papers. "We did not inspect the frame." "Then," said the judge, "you have one story and an unexamined rival story. Until you check the frame, steering habits are only a guess." Mr. Whitfield bowed. "The defense rests on a wrench."

Step 5 · Work the real question

Open PrepTest 142, Section 2, Question 18 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Find the conclusion and the observed result it explains. Note what was done to the subjects during the test. Ask whether that treatment could have caused lasting damage that would produce the same result by itself. The right answer names an alternative explanation the argument never considered. Cross out answers that drift to other groups, other abilities, or a complaint about the evidence that is too vague.