Logical ReasoningDifficulty: Hard

PT117 S3 Q21 Explanation

A smoker trying to quit

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsNecessary Assumption

Keep going in LSAT Lab

  • Save & drill this skill build targeted practice sets from questions like this one

  • Video walkthroughs watch every question solved step by step

  • 81 official LSATs as questions, timed sections & full-length tests

Full official LSAT questions are available through LawHub. This page provides LSAT Lab's explanation, strategy, and review tools without republishing the full official question.

Stimulus

A smoker trying to quit is more likely to succeed if his or her doctor greatly exaggerates the dangers of smoking. Similar strategies can be used to break other habits. But since such strategies involve deception, individuals cannot some other third party provides the warning.

What this question is testing

Necessary Assumption

Your task

Find the assumption the argument requires in order for its conclusion to hold.

Common trap

Answers that would help the argument but aren't strictly required (sufficient, not necessary).

Winning move

Negate each choice — the right one breaks the argument when negated.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
21.

Which one of the following is an assumption on which the

Answer choices

  1. Too Strong: tend to / whatever15% picked this

    People tend to believe whatever doctors

    The argument is definitely insinuating that a person would find a greatly exaggerated warning of danger more compelling coming from a doctor than from themselves. But that's all the author has said on this matter. She hasn't committed herself to the idea that most people ("tend to" = most) believe whatever doctors tell them.

  2. Too Strong: most3% picked this

    Most of the techniques that help people quit smoking can also help people

    The argument is saying that this one technique (of greatly exaggerating danger) is a technique that helps to quit smoking as well as to break other habits. Technically, she doesn't say the same technique works for both, but similar strategies work for other habits. But that's just one technique that crosses over from smoking to other habits. The author hasn't come close to committing herself to the idea that more than 50% of techniques that work for smoking also work for other habits. (The word 'most' is wrong on Necessary Assumption and in Reading Comp, the vast majority of the time we see it.)

  3. Too Strong7% picked this

    The more the relevant danger is exaggerated, the more likely one is to

    Too Strong: the more X, the more Y This is a Volume Dial statement (the more X, the more Y), which is the strongest type of claim on LSAT, because it means that two things have a relationship that extends infinitely in both directions. The author thinks that if the danger of a habit is exaggerated by a third party, it could help someone break their habit. But the author doesn't commit to a precise mathematical idea that if you exaggerate the danger by 15% more, then you increase the likelihood of the habit breaking by 15%. This answer has nothing to do with the conclusion, either. The author isn't arguing that people will be likely to break a habit. We should be hearing about whether or not it's possible to carry off a strategy that involves deception without a third party.

  4. Correct71% picked this

    People generally do not find it easy to

    Why this is right

    We're always very receptive to answers with Ruling Out language (not/no) on Necessary Assumption, since so many correct answers are written in that style. These are the answers we especially should consider negating, to see whether they turn into objections. Would it hurt the argument if we said, "Yo, author -- people generally do find it easy to deceive themselves"? Yes! This author is saying, "Since these strategies involve deception, it will be hard to adopt them unless you have someone else to provide you with the warning." But we can clap back and say, "Why do you need someone else? People usually find it easy to deceive themselves".

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

  5. Too Strong: whenever5% picked this

    A doctor is justified in deceiving a patient whenever doing so is likely to make

    This argument only dealt with one instance in which a doctor would potentially be justified in deceiving a patient. The author didn't sign off on all such cases and say that whenever a deception would make the patient healthier, it's fine for a doctor to deceive the patient. The concept of "justified in deceiving a patient" is totally out of scope.

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free