Hearsay, which refers to out-of-court statements offered to prove the truth of the matter asserted, is generally not admissible at trial unless it falls within one of the recognized exceptions.
Because what has been proven is that in any system of mathematics where you can do basic arithmetic, there will always be true statements that are impossible to prove.
It's a real statement because everything that we are now creating or inventing or discovering, in my opinion, already existed or someone already had the thought for it.
Okay, so let's look at the zero conditional, which is the simplest one, really, and this is for statements which are true in general, they're generally true.