broall wrote:
Every photograph, because it involves the light rays that something emits hitting film, must in some obvious sense be true. But because it could always have been made to show things differently than it does, it cannot express the whole truth and, in that sense, is false. Therefore, nothing can ever be definitively proved with a photograph.
Which one of the following is an assumption that would permit the conclusion above to be properly drawn?
(A) Whatever is false in the sense that it cannot express the whole truth cannot furnish definitive proof.
(B) The whole truth cannot be known.
(C) It is not possible to determine the truthfulness of a photograph in any sense.
(D) It is possible to use a photograph as corroborative evidence if there is additional evidence establishing the truth about the scene photographed.
(E) If something is being photographed, then it is possible to prove definitively the truth about it.
OFFICIAL EXPLANATION
The author argues that since a photograph can be deceptive it can never express the whole truth. Therefore, it can never be used to prove something. The assumption needed to connect these two sentences is that if something cannot express the whole truth then it cannot prove anything. The answer, therefore, is (A).
The other choices are easily ruled out. As to (B), the argument does not state that the whole truth cannot be known, merely that it cannot be known
through a photograph. Choice (C) is similarly flawed. The argument does not state that a photograph cannot express the truth in
any sense, merely that it cannot express the
whole truth. (Again, beware of absolute statements.) Choice (D) is a reasonable assumption to make, but it is not relevant to the argument. Finally, choice (E) contradicts the argument.