Logical Reasoning

PT4 · S4 · Q13 Physician: The patient is suffering

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

  • 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

Start practicing free

Physician: The patient is suffering either from disease X or else from disease Y, but there is no available test for distinguishing X from Y. Therefore, since there is an effective treatment for Y but no treatment for X, we must act on the assumption that the patient has a case of Y.

Conclusion (therefore)

We must act on the assumption that the patient has Y.

Premise (since)

The patient has either disease X or disease Y, but there is no test to distinguish them. There is an effective treatment for Y but no treatment for X.

Evaluate

We have no means of figuring out whether it's X or Y, but if it were Y, we would at least have a chance of helping the patient (whereas we have no way to help if it's X).

Goal

So let's find a principle saying,

13.

The physician’s reasoning could be based on which one of the following principles?

  1. In treating a patient who

    Bad Description

    This outcome doesn't help us conclude that we should assume the patient has Y rather than X. It basically tells us to treat both diseases.

    11% picked this

  2. If circumstances beyond a decision

    Opposite

    Neither part seems to match up here. The decision maker is the physician. She's trying to decide whether to assume the patient has X or Y. Are there circumstances beyond her control that will affect the outcome of her action? I guess if we were being charitable we could say, "the fact that we have a treatment for Y but lack one for X is a circumstance beyond her control that will affect which action she takes". But then the outcome of this answer would be acting like our conclusion was, "Therefore, it's unfavorable that we have a treatment for Y but lack one for X", which is miles away from the actual conclusion.

    1% picked this

  3. When the soundness of a

    Bad Description

    The outcome of this rule is, "We have to test the truth of this assumption. The actual conclusion is, "We should make the assumption that it's Y." Those are very different. The argument isn't trying to conclude that we should test whether it's Y (after all, there is no test that lets us do that). The argument is trying to conclude that we should assume it is Y. This rule doesn't land on that sort of idea at all.

    10% picked this

  4. Correct

    When success is possible only

    Why this is right

    The appeal of this at a glance is that the Outcome seems to be a good match for the Conclusion. This rule would allow us to say, "we should make THIS assumption", and the conclusion is also saying we should make this assumption (that it's disease Y). Does the trigger apply? Is the success of this physician's treatment decision possible only if a circumstance beyond their control is favorable? Ugh. I guess, kind of? Success is only possible if the patient actually has disease Y. There is no treatment for X, so no possible success if the patient has X. Is that circumstance beyond the physician's control? Sure, in the sense that the patient already has the disease. The physician has no control over what disease they got. Also, in the sense that the physician has no control over testing to see whether it's X or Y, since no test exists. So, "success is possible only if we have the favorable circumstance that the patient actually has disease Y". And according to the outcome of this rule, our strategy should be based on the assumption that this patient has disease Y.

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

    58% picked this

  5. When only one strategy carries

    Bad Description

    The trigger of this is lovely, since only the strategy of treating disease Y has any possibility of success. Is the conclusion saying, "Therefore, circumstances must as much as possible be changed to fit the strategy of treating disease Y"? No, it's just saying, "Therefore, we should assume that the patient has disease Y."

    20% picked this

Continue the review in LSAT Lab

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

Save and practice this skill
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