PT6.S3.Q13 - Trade and yeti sightings analogy

xuzuqiao

In another discussion post about this question (the only other post about this question), one of the responses stated:

the crux of the argument lies in the second part of the second sentence where the author makes an explicit attempt at underlining the underlying logic: "but the absence of sightings cannot prove that it does not (exist)".
In lawgic that's: if there's absence, then we cannot prove non-existence.
Absence --> /prove

In order to weaken the argument, we need to find something that's loosely along the lines of: if there's absence, then that might actually mean non-existence.

(E) encapsulates this best.

But his underlying logic doesn't really make sense to me. If Absence of sightings -> cannot prove yeti does not exist, then the contrapositive is: prove yeti does not exist -> some sightings. The contrapositive doesn't make intuitive sense. If we prove that the yeti does not exist, then there must be some sightings of the yeti? That sounds like the complete opposite of what is necessary to prove something does not exist.

How does answer choice E weaken the argument? Is focusing on the underlying logic in the final sentence the best way to approach this question?