Ah, your doing it again...
You mean evidence and/or proof.
In science there is no proof, only evidence. Colloquially proof is a large amount of supporting evidence such that doubt is minimal. It's not evidence/proof that is the question as far as I can see i.e. if I was replying to me I'd highlight what is accepted as evidence. To me evidence is something which supports a claim, which indicates a particular outcome over others and which could convince others of the truth of a claim.
If you are talking about historical evidence then historians look to decide what was most likely to have happened and will assess the reliability of the sources, how independent of each other they are and how many independent sources there are.
What was your point though?