PrepTest 112

[lcid:3546] Prep Test 112 LSAT — Logical Reasoning — S3 Logical reasoning

Question prompt

While it was once Remaining source text redacted.
Why the credited answer is right

Credited answer: A

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

Argument or Facts

Argument

Valid or Flawed

Flawed

Question Type

Errors in Reasoning Questions

Stimulus Summary

Old belief - Both neuroses and psychoses could be treated with psychotherapy
New belief - Psychoses are best treated with drugs
Conclusion - Psychoses are caused by organic factors and the environment plays no role in them

Answer Anticipation

This argument is an interesting mishmash of two common types of logic on the exam - comparisons, and causation. The argument compares the causes and treatments for neuroses and psychoses.
We get a more complete picture of neuroses than psychoses. According to the stimulus, neuroses are “caused by environmental factors” and are treated appropriately with psychotherapy.
Psychoses, on the other hand, are best treated with medications. From this, the argument concludes that they must not be caused by environmental factors, but rather by organic ones.
However, the conclusion goes to quite an extreme - it states that environmental factors have “nothing to do” with psychoses. Such an extreme conclusion will almost always directly be involved in a flaw, as it’s hard to prove something so absolute. And here, the premises fall well short of it.
While psychoses aren’t best treated by the same approach as another malady that is caused by environmental factors, that doesn’t mean environmental factors play no role in psychoses. Also, just because they’re best treated by organic factors (“biochemical”) doesn’t mean that they’re caused by only those types of factors. It’s possible that the best treatment for certain environmentally caused diseases is medicine - for example, ingesting poison. And it’s also possible that these psychoses are caused by organic factors, but that environmental factors can trigger them or make them worse.
Since this question stem asks us to find a possibility that this argument overlooks, let’s find something bringing up one of the possibilities we just mentioned, or any other that suggests environmental factors may play a role in psychoses.

Answer choices

  1. A
    the organic conditions that Remaining source text redacted.
    Why choice A matches the stem
    This answer establishes that even if psychoses are caused by organic conditions, those conditions are affected by environmental conditions. That completely undermines the conclusion that environmental factors have “nothing to do” with psychoses, and so this is the correct answer.
  2. B
    the symptoms of mental Remaining source text redacted.
    Why choice B is not credited
    The argument assumes that this is true - that psychoses (which it concludes are caused by organic factors) are best treated with medicine. As such, it’s not something that the argument ignores.
  3. C
    organic illnesses that are Remaining source text redacted.
    Why choice C is not credited
    The argument is about psychological conditions, so this answer is out of scope.
  4. D
    the nature of any Remaining source text redacted.
    Why choice D is not credited
    The argument assumes that psychoses must have an organic cause because they have an organic/biochemical treatment, so this is something the argument assumes instead of overlooks.
  5. E
    organic factors having little Remaining source text redacted.
    Why choice E is not credited
    First, the stimulus talks about neuroses caused by environmental factors, so there may be other neuroses that have organic factors. Second, the conclusion is about the causes of psychoses, not neuroses, so there’s no assumption being made on this front.

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