Logical Reasoning · Necessary Assumption

PrepTest 116 · Section 3 · Question 23

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

Step 1 · Pre-Question Guidance · read this first

Question type

Necessary Assumption

The one idea it tests

Calling two statements inconsistent assumes they really clash; here the bridge is that a consistent view cannot call something worthy yet say not to do it.

The basic logic

The argument shows someone said A on some days and B on other days, then calls the view inconsistent. But A (this is a worthwhile aim) and B (do not do it) only clash if a consistent view cannot hold both. The missing plank links 'worthwhile aim' to 'should be done'. Negate it and the two claims can live side by side.

Tiny words that decide it

“however”
“so”
“clearly”
“should not”

Playground logic

Frankie's patties: he says a treehouse is a worthwhile aim, and he says the class should not build one. Sharon's top bun: Frankie is inconsistent. Her secret sauce: a consistent person never calls something worthy and also says not to do it.

Step 2 · The kid story

Frankie's Treehouse Flip-Flop

On Monday, Frankie tells the class that building a treehouse is a wonderful goal. On Wednesday, he tells Ms. Rivera the class should not build a treehouse. Sharon pounces. 'You flip-flopped! Your treehouse view is totally inconsistent!' Frankie crosses his arms. 'It is a wonderful goal. We just should not do it this year. We have no wood and the only tree is the one Mr. Whiskers lives in.' Priya nods slowly. 'Sharon, your argument only works if a consistent person can never call something a worthwhile aim and also say not to do it. Frankie just showed a way both could be true.' Sharon taps her chin. 'Fine. Then I need a better argument.' Lulu writes on her clipboard: worthy is not the same as do it now.

Step 3 · Try the model question

Sharon: Frankie has said several times that building a treehouse is a worthwhile aim. Yet on other days he has said the class should not build a treehouse. So Frankie's view about the treehouse is plainly inconsistent.

Sharon's reasoning depends on which one of the following?

Step 4 · The courtroom tale

The Garden Club Contradiction

In a fictional lawsuit, a garden club member sues the club president for being 'inconsistent'. Her lawyer reads aloud: the president said a new rose garden is a worthwhile aim, and then said the club should not plant one. 'A contradiction, Your Honor!' Mr. Whitfield adjusts his suspenders. 'Only if a consistent view can never call something worthy while saying not to do it. My client said the garden is worthy but the club has no money and no sunny land. Those can both be true.' The judge sighs. 'Counsel, your case rests on that hidden link. Without it, there is no contradiction.' The case is dismissed, and the club plants daisies.

Step 5 · Work the real question

Open PrepTest 116, Section 3, Question 23 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Find the two claims that are said to conflict and the conclusion that the view is inconsistent. Ask whether those two claims truly contradict, or whether they could both be held. Predict the bridge that makes them clash: something like 'worthwhile aim means it should be done'. Negate each answer; the right one, when denied, lets the two claims fit together and sinks the charge of inconsistency. Watch for answers that are stronger or off topic.