PrepTest 157

[lcid:3725] Prep Test 157 LSAT — Logical Reasoning — S2 Logical reasoning

Question prompt

Columnist: Consent forms filled Remaining source text redacted.
Why the credited answer is right

Credited answer: D

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument

Valid or Flawed

Flawed

Strategy Overview

Argument or facts? Always argument, so identify premises and conclusions of argument Anticipate why the premises are not enough to prove that the conclusion is true. Checking to see if a common logical fallacy is committed is very helpful.

Answer Anticipation

On an Errors in Reasoning question, we should take the time to articulate why the premise or premises aren't enough to prove that the conclusion is true. To help organize our thought process, we can think about the common flaws that arguments commit over and over again. Many test-takers find this reasoning persuasive. After all, the subjects filled out forms accepting the risk of receiving a placebo or ineffective treatment. So, it seems like the columnist has a point — subjects don't necessarily resent being given placebos or ineffective treatment. But before we become too enamored with their reasoning, let's try to poke some holes in it. This is where our common sense or life experience can help out. Do you ever agree to something you later regret? We have! (Literally, almost every time we make plans to go out!) Notice that the columnist doesn't make an evaluative or normative claim about whether subjects should be or have the right to be resentful. The columnist's conclusion is a factual one — the consent forms undermine the medical ethicists' argument that subjects actually resent being given placebos. The subjects could certainly accept the risks when signing up but later change their minds. We can think of this flaw as a "concept switch" or equivocation. However, it would perhaps be more precise to classify it as a temporal flaw. The columnist's premises address subjects' feelings before a study takes place, but the conclusion discusses their feelings after the study. (Notice the shift in verb tense between the premise and conclusion. The premises say the subjects "filled out" the consent forms "prior to their participation in tests." The conclusion says the test subjects may not "resent" being given placebos or ineffective medicines.) Of course, one's feelings can change over time! The correct answer choice will almost certainly describe this flaw, so let's keep it in mind as we assess the answer choices.

Answer choices

  1. A
    infers that two phenomena Remaining source text redacted.
    Why choice A is not credited

    The columnist's argument doesn't infer that two phenomena are associated. The columnist's conclusion discusses two phenomena — subjects resenting being given placebos and resenting being given ineffective medicine. But the author doesn't say they're associated — just that the consent forms cast doubt on whether either phenomenon occurs.

  2. B
    uses as evidence the Remaining source text redacted.
    Why choice B is not credited

    It's not a flaw that the columnist uses the opinions of unqualified people to make this conclusion. In fact, the columnist's conclusion asserts that test subjects do not actually resent being given placebos or ineffective treatments. To draw that conclusion, the columnist must rely on the test subject's opinions!

  3. C
    uses evidence drawn from Remaining source text redacted.
    Why choice C is not credited

    The columnist doesn't even use a sample to draw this conclusion. As far as we can tell, the columnist uses the consent forms of all subjects who sign up for tests of experimental medicines. If we knew that, for instance, the columnist only looked at subjects who were paid to sign up for these tests, this would be an appealing answer choice. But the argument doesn't give us any reason to think the consent forms the columnist cites are unrepresentative of the test subject's general feelings.

  4. D
    takes for granted that Remaining source text redacted.
    Why choice D matches the stem

    Here we go! This matches our anticipation, so we can be pretty confident that it's the correct answer. To be sure, we can apply our usual analysis to this choice.

    When we see "takes for granted" on an Errors in Reasoning answer choice, the question we should ask ourselves is, "Does the author believe this, and would this strengthen the argument?"

    In this case, the columnist definitely believes that "most test subjects do not change their attitudes" toward the risk of taking ineffective substances after they take ineffective substances. After all, the columnist uses evidence about what the subjects agree to before the study to conclude how they feel after they take the study. (Notice the shift in verb tense between the premise and conclusion. The premises say the subjects "filled out" the consent forms "prior to their participation in tests." The conclusion says the test subjects may not "resent" being given placebos or ineffective medicines.) So, the columnist must believe that the subjects' attitudes do not change between filling out the forms and being given ineffective treatments.

    As we discussed in the Answer Anticipation section, this assumption isn't necessarily warranted. People change their minds all the time. It would be very understandable and not at all surprising if a test subject given an ineffective treatment for a disease they're suffering from would change their mind and resent the treatment.

    Additionally, this unwarranted assumption strengthens the columnist's argument. If test subjects do not change their mind after filling out the consent form, they will continue to accept the risk of taking ineffective treatment even after being given an ineffective treatment. Therefore, those forms would cast doubt on the medical ethicists' claims that subjects resent being given ineffective medicine in these studies.

    Since the columnist relies on this unwarranted assumption to make their conclusion, this is a flaw in their argument. We can select (D) confidently.

  5. E
    draws a conclusion that Remaining source text redacted.
    Why choice E is not credited

    The columnist doesn't draw a conclusion about a moral issue. In fact, the columnist's conclusion isn't evaluative or normative; the columnist doesn't argue that subjects should not be or have no right to be resentful. The columnist's conclusion is a factual one — the consent forms undermine the medical ethicists' argument that subjects actually resent being given placebos.

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