Hi.
My personal opinion is that generally ‘proof’ can mean different things to different people at different times. I have often had people suggest that I cannot prove that God exists. Scientifically, this might be true, but the proof I have is enough for me. There are many areas in science (including maths) that can be shown to be true beyond reasonable doubt. But there will always be those that choose to disbelieve it - for instance, those who do not believe in a physical existence at all. And there are areas in science that we are not able to prove beyond reasonable doubt. Some will take them as so certain as to be ‘proof’ while others will continue to be uncertain at best. So the term ‘proof’ (often just like the term ‘fact’) can be quite a flexible and personal thing - whether or not it should.
Matt