Logical Reasoning · Flaw

PrepTest 151 · Section 3 · Question 7

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

A rule about what people expect is attacked with examples of what actually happened.

The basic logic

The theory talks about hopes before acting. The counterexamples talk about results after acting. Those are different things, so the evidence misses the target. This is a Slippery Word or Scope Shift.

Tiny words that decide it

“only”
“cannot”
“because”

Playground logic

Priya's rule: Kevin only picks foods he expects to taste good. Marcus says the rule is wrong because one pick tasted awful. But a bad result does not prove a bad expectation. Marcus shifts from 'expected' to 'turned out.'

Step 2 · The kid story

Kevin's Lunch Rule

Priya had a theory. "Kevin only picks foods he expects will taste good. That's his whole system." Marcus burst out laughing. "Wrong! Yesterday at the fair, Kevin picked the pineapple pizza with sardines, and he said it tasted like a sock." Kevin nodded sadly. "It really did." Marcus spread his hands. "So the rule is busted." Priya calmly sipped her juice box. "Kevin, when you picked it, did you think it would be good?" Kevin's eyes lit up. "I thought it would be the best pizza ever! Pineapple AND fish? Two flavors!" Priya turned to Marcus. "My rule is about what he expects, detective. Not about how it turns out. A bad surprise doesn't break it."

Step 3 · Try the model question

Priya says Kevin only picks foods he expects will taste good. Marcus replies that this must be false, because Kevin once picked a pizza that tasted awful.

Marcus's reasoning is flawed because it

Step 4 · The courtroom tale

The Case of the Leaky Umbrella

In a fictional shop dispute, the store's policy said customers only buy items they expect will work well. The opposing lawyer told Judge Hale, "Your Honor, that policy is nonsense. This customer bought an umbrella that leaked like a sieve!" Mr. Whitfield adjusted his suspenders. "Your Honor, did she expect it to leak when she bought it?" The customer shook her head. "I thought it was perfect." The judge chuckled. "The policy talks about expecting. Your evidence talks about how it turned out. Those are not the same thing."

Step 5 · Work the real question

Open PrepTest 151, Section 3, Question 7 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

First, write the theory in your own words and circle its key word about the mind (what people think will happen). Then write the evidence and circle its key word about the world (what actually happened). Ask whether the evidence really hits the theory. Look for the answer that names the gap between the two. Cross out flaws the argument does not commit, like circles or counts it never makes.