Logical Reasoning · Weaken

PrepTest 116 · Section 2 · Question 4

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

Step 1 · Pre-Question Guidance · read this first

Question type

Weaken

The one idea it tests

When an argument says 'X arrived, then things changed, so X caused it,' pop it with another cause that showed up around then.

The basic logic

The patty shows a big change after something new arrived. The top bun blames the newcomer. The secret sauce is that nothing else could explain the change. Weaken by naming a different cause whose timing fits just as well.

Tiny words that decide it

“since”
“before”
“thus”
“caused”

Playground logic

Marcus's burger: tomato harvests dropped after Tommy joined the garden club, so Tommy caused the drop. That is a Rooster: timing taken as cause. Pop it with another suspect who arrived right before Tommy, like a swarm of hungry beetles.

Step 2 · The kid story

Who Ate the Tomato Harvest?

The school garden club used to pick baskets full of tomatoes every week. Then Tommy joined. Since then, the baskets have been almost empty. Marcus put on his detective hat. "The evidence is clear. Tommy joined, the tomatoes vanished. Tommy is the culprit." Tommy gasped. "I only hid candy in the toolshed, I swear!" Priya opened the garden notebook. "Look at this. A week before Tommy joined, Ms. Rivera wrote: 'Spotted beetles on the tomato leaves.' Beetles eat tomato plants." Lulu wrote on her clipboard: New thing arrived, things got worse. But ANOTHER new thing arrived right then too. Marcus took off his hat. "So the beetles were the real newcomer?" "Maybe," said Priya. "Either way, your case just got a lot weaker."

Step 3 · Try the model question

Before Tommy joined the garden club, the club harvested many tomatoes each week. Since Tommy joined, the weekly harvest has been far smaller. Thus, Tommy's joining the club caused the tomato harvest to shrink.

Suppose each choice below is accurate. Which one hurts the argument most?

Step 4 · The courtroom tale

The Case of the Silent Choir

The prosecutor pointed at a new choir director. "Your Honor, before she arrived, the choir won every contest. Since she arrived, they have lost them all. She ruined the choir!" Mr. Whitfield stood and snapped his suspenders. "Your Honor, I call the school nurse." The nurse testified: "The week before the new director started, a nasty throat bug swept through the choir. Half the singers lost their voices." Mr. Whitfield turned to the jury. "Two newcomers, folks. A director and a bug. The prosecution only looked at one of them." Judge Lin raised an eyebrow. "The timing fits the bug just as well. The prosecution's case is considerably weaker."

Step 5 · Work the real question

Open PrepTest 116, Section 2, Question 4 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Find the top bun: a newcomer caused a change. Find the patty: the change came after the newcomer arrived. Ask: what else could have arrived or changed around then? The best weakener names a rival cause with matching timing. Be careful with choices that actually support the newcomer as the cause, or that describe things that stayed the same and so cannot explain any change.