Logical Reasoning · Flaw

PrepTest 137 · Section 2 · Question 13

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

The argument trusts the people who use something because they know it, but forgets that others may avoid it because they know it too.

The basic logic

The patty: most people reject X, but frequent users like it, and frequent users know X well. The top bun: X is probably good. The hidden sauce: the non-users don't know X. Look for the answer that points out the non-users may have stayed away precisely because of what they know. It is a Weird Sample: the fans picked themselves.

Tiny words that decide it

“most”
“regularly”
“familiar”
“likely”

Playground logic

Marcus says the kids who ride the Twisty Slide every day know it best, so their love proves it's great. But Owen may skip it because he knows it too well. The fans picked themselves.

Step 2 · The kid story

The Twisty Slide Debate

Most kids at recess stay away from the new Twisty Slide. But Marcus and two friends ride it every single day. "We ride it all the time, so we know it best," Marcus said. "And we think it's awesome. So it probably is awesome." Priya sipped her juice box. "Marcus, Owen rode it last week. He knows it too. He got static shock and his hair stood straight up. That's why he never goes back." Owen nodded sadly. His hair was still a little puffy. "Maybe lots of kids skip it because they know exactly what it does," Priya said. Marcus thought about it. Then he went down the slide again. Zap. "Okay," he said, hair sparking, "it's awesome AND shocking."

Step 3 · Try the model question

Most kids at recess don't think the Twisty Slide is fun. But the kids who ride it every day love it. Since the kids who ride it every day know the slide best, the Twisty Slide is probably fun.

Which one of the following points to a weakness in Marcus's reasoning?

Step 4 · The courtroom tale

The Spicy Sauce Witnesses

A hot-sauce maker was sued for calling its sauce "beloved." "Your Honor," said its lawyer, "most shoppers never buy it. But our loyal buyers, who buy it weekly, rave about it. They know it best, so it must be beloved." Mr. Whitfield stood, tugging his suspenders. "Your Honor, I tasted it once. My eyebrows are still recovering. Many shoppers may skip it exactly because they know what it does." The judge nodded. "So the sauce's fans picked themselves. The people who stay away may know it just as well." She turned to the lawyer. "Your witnesses love the sauce. That does not make the rest of the town wrong."

Step 5 · Work the real question

Open PrepTest 137, Section 2, Question 13 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Name the two groups in the patty: those who use the thing and those who don't. Ask why the argument trusts the users: usually their familiarity. Then ask whether the non-users might also be familiar and stay away for that very reason. Pick the answer that raises that possibility. Cross out answers describing moves the argument never makes.