Logical Reasoning · Parallel Flaw

PrepTest 129 · Section 2 · Question 8

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

Step 1 · Pre-Question Guidance · read this first

Question type

Parallel Flaw

The one idea it tests

Spot the 'I've never seen it, so it doesn't exist' flaw and find its twin.

The basic logic

Label the original: personal lack of evidence leads to a flat claim that something does not exist (No Footprints). The twin needs the same strength: never personally saw it, so it absolutely isn't there. Check both the kind of evidence and how strong the conclusion is.

Tiny words that decide it

“never”
“no”
“so”

Playground logic

Kevin says there is no such thing as a kid who hates pineapple pizza, because he has never met one. That's No Footprints: not seeing something is not proof it isn't there. The twin needs the same move, with a definite 'there are none.'

Step 2 · The kid story

Kevin's Pineapple Pizza Theory

Kevin made a big announcement at lunch. "There is no such thing as a kid who hates pineapple pizza." Sharon raised an eyebrow. "How do you know?" "Because in all my years of pizza parties, I have never met one." "Kevin, you are nine." "Nine years of pizza parties!" Frankie, who loved debating, said, "Maybe the pineapple haters just don't come to your parties. Because you always order pineapple." Kevin paused, mid-bite. Priya sipped her juice box. "Not finding something doesn't prove it isn't there. Maybe you weren't looking in the right places." Lulu raised her hand. "I don't like pineapple pizza." Kevin dropped his slice. Biscuit caught it, and confirmed he liked pineapple.

Step 3 · Try the model question

Kevin: There is no such thing as a kid who hates pineapple pizza. In all my years of pizza parties, I have never met one.

Which one of these has reasoning most like Kevin's questionable reasoning?

Step 4 · The courtroom tale

The Case of the Missing Mermaid

A sailor sued the aquarium for its mermaid exhibit. "Your Honor, there is no such thing as a mermaid. I have sailed for forty years and never once seen one." Mr. Whitfield, representing the aquarium, rose. "Your Honor, I have never seen my client's left sock disappear in the dryer, yet I am told it happens." The judge chuckled. "Your point, Counselor?" "Not seeing something is not proof it does not exist. My client may not have mermaids. But the sailor's argument does not prove that." The judge nodded. "The sailor's eyes are not the ocean." The mermaid exhibit, for the record, was a very large fish wearing a wig.

Step 5 · Work the real question

Open PrepTest 129, Section 2, Question 8 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

First label the original flaw: never encountered it, so it does not exist, with a certain conclusion. Then check each choice for the same evidence type (personal lack of sightings) and the same conclusion strength (a flat 'none'). The match will have both the same move and the same confidence.