Proof and acceptance
In this plane of existence the truth can be approached, reasonably ascertained, even known but it cannot be proven. While the truth in its absolute state is pure and consistent, on this plane, it can only be a reasonably sure thing but not an absolute. Whatever we do here is tainted, so all we can do is suspect there is a truth, but we can't prove it. Nothing can be absolutely proven. We can arrive at truth beyond a reasonable doubt, but it is not written in stone.
Even the equation one equals one can't be proven. We have to accept it on faith and proceed and build upon it. Nothing in the universe totally equals something else. There is no such thing. We accept equality because it is convenient, and in good faith use it as a premise, but we can't prove it.