Re infinity, we are discussing matters beyond the scope of scientific proof, and are firmly in the realm of philosophy. We can agree on that, can we not?
I would like to agree, but scientists and mathematicians frequently talk of this or that being infinite, or happening an infinite number of times, or, even worse, saying that something can become infinite, or stop being infinite. This is fine, as long as they make it clear that what they are talking about is the mathematically infinite, for which, in my opinion, a less confusing term would be unbounded.
On the other hand, what kind of proof could be presented to show that there was no existence of any kind before a given moment?
Absolutely none! In fact, I suspect that the nearest one can come to proof/falsification in this matter is the seemingly logical argument that there can never have been a time when there was nothing, or there would be nothing now. One trouble with that is that there are many who want to question the nature of nothing.
