LSAT 144 | Section 4 | Logical Reasoning: Q15

LR Question 15 Explanation

QUESTION TEXT: Armstrong: For the treatment of a particular disease…

QUESTION TYPE: Flawed Reasoning

CONCLUSION: We shouldn’t use nutritional supplements to treat the disease.

REASONING: Dr. Sullivan is a bad, bad man.

ANALYSIS: This is one of the worst reasoning errors you can make, but in real life we do it all the time. This is an ad hominem flaw. More specifically, this is concluding we shouldn’t do something just because someone we don’t like says we should.

Something isn’t wrong just because Dr. Sullivan has a conflict of interest. If that was enough, then we could ruin society by paying Dr. Sullivan to go around recommending good ideas. Then we’d be forced to stop doing good things merely because he recommended them. Sullivan!

The author should have argued about the actual effects of supplements, and not merely what Sullivan says about them.

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1. The stimulus never switches terms. The definitions of “supplement” are (1) something you add to something else, or (2) a nutritional supplement, or (3) a separate section added to a periodical, or, in geometry, (4) the amount by which an angle is less than 180 degrees.
   So….only the second one is used in this stimulus.
2. This was a bit of a trap. The author was rejecting Johnson’s authority. This answer says “relies…on”, so it’s completely wrong.
3. What emotion?
   Example of flaw: Think how happy you were when you had adequate zinc in your diet, during your youth. Take zinc today.
4. CORRECT. This answer describes an ad hominem flaw. The author attacked Dr. Sullivan’s motives, rather than his evidence. The supplement might be good despite Sullivan’s motives.
5. The author didn’t say we can’t use supplements along with pharmaceuticals. They said we shouldn’t.