Historian: We can learn about the medical history of individuals through chemical analysis of their hair. It is l...

Ravi on October 1, 2019

@RitaW,

Let's look at (B).

(B) says, "Some people in Beethoven’s time did not ingest mercury."

We're looking for a necessary assumption in this argument. We can use
the negation test to find the right answer. The right answer, when
negated, will make the argument fall apart because it is *required*
for the argument.

(B)'s negation is "no one in Beethoven's time did not ingest mercury."
This means the same thing as saying that everyone in Beethoven's time
ingested mercury.

The argument is assuming that finding mercury in Beethoven's hair
would mean something significant. However, if everyone in Beethoven's
time had mercury (and presumably then had mercury in their hair), then
it wouldn't matter if we found mercury in Beethoven's hair because it
was in everyone's hair. Thus, mercury in his hair wouldn't tell us
anything about whether he had a venereal disease since it wouldn't be
a distinguishing factor. The negation of (B) wrecks the argument, so
we know that (B) is a necessary premise. Thus, it's the correct
answer.

Hope this helps. Let us know if you have any other questions!