LSAT 148 | Section 2 | Reading Comprehension: Q24

RC Question 24 Explanation

DISCUSSION: X rays are mentioned on line 5. The author uses X rays in order to show that brain scans do have one valid use: they help us see inside the body, and can help diagnose medical issues.

This is merely a rhetorical technique. The author qualifies their argument: they’re not opposed to brain scans in every use case. This helps prevent people from misunderstanding the argument. It also helps highlight the difference between this valid use of brain scans and their invalid use in subtraction analysis.

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1. CORRECT. Simple as that. Everyone knows what an X ray is. So, mentioning X rays helps us understand how brain scans have at least one good use case: they can help us diagnose medical issues. This valid use serves in contrast against the dubious use in psychology.
2. X rays aren’t new technology, they’ve been around for decades. Brain scans have too, I think. Certainly the passage doesn’t mention newness.
3. The passage says that brain scans are similar to X rays. If the author wanted to say they were less precise, they would have said something like “Less precise than X rays, brain scans nonetheless….”
4. The “theory that brain scans support” is the modular theory of mind. X rays have nothing to do with this theory, for or against. X rays only related to brain scans in that both X rays and brain scans have medical uses.
5. The passage didn’t say how brain scans developed. In fact, the words “similar in principle” suggest that in practice X rays and brain scans are different.