Logical Reasoning · Flaw

PrepTest 111 · Section 3 · Question 2

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 can be flawed because it ignores part of its own evidence, the very part that points the other way.

The basic logic

Look at the quote or fact used as the patty. Does the arguer read all of it? If one piece of the evidence shows the opposite of the top bun, the argument skipped it. That skipped piece is the flaw.

Tiny words that decide it

“although”
“even”
“not”
“provides evidence”

Playground logic

Marcus quotes Aunt Rosa to prove she thinks the robot vacuum is a real family member. But her own words start with "I know it is only a machine," which shows she knows the difference. The top bun stands on half the patty and throws the other half away.

Step 2 · The kid story

Aunt Rosa and the Robot Vacuum

Aunt Rosa's robot vacuum, Zippy, bumped into the couch one last time and stopped forever. Aunt Rosa sighed. "I know it was only a machine, but it feels like we lost a member of the family." Marcus spun around. "Aha! Case closed! Aunt Rosa thinks a vacuum is a person! She can't tell gadgets from people anymore!" Lulu tapped her clipboard. "Marcus, read the whole thing." "I did. 'Member of the family.' Boom." "She also said 'I know it was only a machine.' That's the part where she says she knows it is a machine." Marcus squinted. "That part was boring, so I skipped it." Priya smiled. "The boring part is the part that sinks your case." Aunt Rosa patted Zippy. "I still miss it," she said.

Step 3 · Try the model question

Aunt Rosa said, "I know it was only a machine, but it feels like we lost a member of the family." Marcus says this proves Aunt Rosa can no longer tell the difference between machines and people.

Marcus's reasoning is most open to criticism on which ground?

Step 4 · The courtroom tale

The Case of the Weeping Baker

The prosecutor waved a note. "Your Honor, the baker wrote: 'I know the gingerbread house is only cookie, but tearing it down felt like losing my own home.' Clearly he believes he lives in a cookie!" Mr. Whitfield rose slowly, suspenders creaking. "Counsel, kindly read the first half." The prosecutor coughed. "'I know the gingerbread house is only cookie.'" "And what does that say?" "That he knows it is only cookie." "So the note itself shows he knows the difference between a cookie and a home?" The prosecutor sat down. The judge chuckled. "Next time, read the whole note before calling the man confused."

Step 5 · Work the real question

Open PrepTest 111, Section 3, Question 2 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Find the top bun: the claim about what someone believes or can do. Then read the evidence word by word, including any 'although' or 'even though' part. Ask: does some piece of the evidence actually show the opposite of the conclusion? Pick the choice that names the skipped part. Be wary of choices that talk about the speaker's personal worth, other people, or things the argument never mentions.