LSAT Explanation PT 28, S3, Q16: Historian: We can learn about the

LSAT Question Stem

Which one of the following is an assumption on which the historian's argument depends? 

Logical Reasoning Question Type

This is a Necessary Assumption question. 

Correct Answer

The correct answer to this question is B. 

LSAT Question Complete Explanation

Let's first analyze the structure of the argument in the passage. The historian is discussing the use of chemical analysis of hair to learn about individuals' medical history. The argument's structure is as follows:

Premise 1: Mercury was commonly ingested in Beethoven's time to treat venereal disease.

Premise 2: Some people hypothesize that venereal disease caused Beethoven's deafness.

Conclusion: If researchers find a trace of mercury in Beethoven's hair, we can conclude that the hypothesis that venereal disease caused his deafness is correct.

The question type is Necessary Assumption, and we are asked to find an assumption on which the historian's argument depends.

Now, let's discuss each answer choice:

a) None of the mercury introduced into the body can be eliminated.

This answer choice is not necessary for the argument. Even if some of the mercury can be eliminated from the body, the presence of mercury in Beethoven's hair could still support the conclusion. The argument doesn't require that none of the mercury can be eliminated, only that enough remains to be detected.

b) Some people in Beethoven's time did not ingest mercury.

This is the correct answer. If everyone in Beethoven's time ingested mercury, then finding mercury in Beethoven's hair would not necessarily indicate that he had a venereal disease. The argument relies on the assumption that not everyone ingested mercury, so finding it in Beethoven's hair would be significant evidence supporting the hypothesis.

c) Mercury is an effective treatment for venereal disease.

This assumption is not necessary for the argument. The argument does not depend on the effectiveness of mercury as a treatment for venereal disease, only that it was commonly ingested for that purpose.

d) Mercury poisoning can cause deafness in people with venereal disease.

This answer choice is not necessary for the argument, as it introduces an alternative cause for deafness (mercury poisoning) that is not part of the historian's argument. The argument's conclusion is focused on venereal disease causing the deafness, not mercury poisoning.

e) Beethoven suffered from psychological problems of the same severity as Newton's.

This assumption is irrelevant to the argument. The argument is about the cause of Beethoven's deafness, not the severity of his psychological problems compared to Newton's.

In summary, the correct answer is B because it is a necessary assumption for the historian's argument. If everyone in Beethoven's time ingested mercury, then finding it in his hair would not be significant evidence supporting the hypothesis that venereal disease caused his deafness.