PrepTest 116 · Section 2 · Question 22 (Parallel Flaw)

Step 1 · Pre-Question Guidance · read this first

Question type

Parallel Flaw

The one idea it tests

When two views compete and a test cannot favor both, the test might still favor neither.

The basic logic

X-ray the argument: two rival views fit everything gathered up to now; an upcoming check cannot agree with both; so it will prove one right. The flaw is Only Two Doors: both could be wrong. Find the choice with the same skeleton and the same hole.

Tiny words that decide it

“both”
“cannot both”
“will confirm”

Playground logic

Lulu says the hamster is named Peanut, Tommy says Pickles, and the new name tag cannot say both, so the tag will prove one of them right. The top bun ignores a third door: the tag might say Waffles.

Step 2 · The kid story

The Name Tag Showdown

The class hamster had a smudged sign on its cage. Lulu said the smudge spelled Peanut. Tommy said it spelled Pickles. Honestly, both readings fit the smudge. "Ms. Rivera is hanging a brand new name tag tomorrow," said Marcus. "It cannot say both names. So tomorrow, either Lulu or Tommy will be proven right!" Priya slurped her juice box. "Or it says something else." Marcus frowned. "Like what?" "Like Waffles." The next morning, the new tag said WAFFLES in giant letters. Lulu and Tommy were both wrong. Lulu wrote: a test that cannot agree with both of you can still disagree with both of you. Only Two Doors is a trap when there is a third door.

Step 3 · Try the model question

Lulu thinks the class hamster is named Peanut, and Tommy thinks it is named Pickles. Both readings fit the smudged sign. The new name tag cannot say both names. So when the tag is hung, it will prove either Lulu or Tommy right.

Which argument goes wrong in the way most like the one above?

Step 4 · The courtroom tale

The Two Clocks

Two neighbors argued about when the fence fell. Mr. Lark said noon. Ms. Dunn said three. "Both stories fit the muddy footprints," said the judge. Mr. Whitfield beamed. "The weather station's wind log will settle it! It cannot point to both noon and three, so it will prove one neighbor right." A clerk read the log aloud. "Big gust at seven in the morning." The courtroom went quiet. Mr. Whitfield tugged his suspenders. "Ah. I assumed only two doors. The wind used a third one." The judge chuckled. "Two wrong answers can still lose to a third."

Step 5 · Work the real question

Open PrepTest 116, Section 2, Question 22 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

X-ray the stimulus: two rivals fit the evidence, a coming check cannot support both, so it will crown one. Name the flaw: it ignores that both could be wrong. For each choice, check two things: does it share this skeleton, and does it share this exact hole? Reject choices that are flawed in another way and choices whose conclusion is safely limited.