One of the common misconceptions of science (that even those with science degrees fall prey to) is the idea of a “scientific proof.” Science is not in the business of “proving” theories (or laws). Anyone that says science has “proved” so and so in their discussions does not really understand science. When we say something has been “proven” we are in effect claiming finality, that is to say, there is nothing in the future that can overturn the status of the theory.
But that is not how science works. Everything in science is tentative. And yes, I mean EVERYTHING. When we judge competing theories we do so by evaluating and analyzing the evidence for it and contrasting it with the alternative theories. The theories we accept are contingent on the best available evidence. As such, with new evidence the accepted theories can be challenged and/or replaced. Thus regardless of our confidence level in the status of a particular theory, however unlikely it might be, there is a probable possibility that it might be wrong. If such a possibility exists then by definition it cannot be said to be “proven.”
The possibility might seem unlikely but that always seems to be the case given our prejudices. Facts are based on our best understanding and if our understanding changes tomorrow so will our facts. Thus there is nothing that is “scientifically proven”–the phrase itself is a contradiction. What we can say, at best, is that a particular theory is very unlikely to be false, but saying that it had been proven we are then conflating mathematical theorems with scientific theories. As Karl Popper once wrote,
“In the empirical sciences, which alone can furnish us with information about the world we live in, proofs do not occur, if we mean by ‘proof’ an argument which establishes once and for ever the truth of a theory.”