Sometimes a question can have multiple answers where all of them share some kind of evidence but none of them can be a [strict — right — 100% sure that it is the answer — what else?] answer.
Things that I have been thinking about but I do not want to use:
if the study of science is called reasoning, which means giving evidence (I am thinking of using "reasonable answer"). But reasonable answer does not mean that it is 100% accurate answer.
the word logic can involve math and philosophies, so it is not a word that I can use — because there is no "right" philosophy.
What else I can use for the word before the last in my sentence?