Proof is the static part of logic (as, for instance, a proof that the circle cannot be "squared"). There is no temporal element in a formal proof. We approach such proofs as though all of its pieces are simultaneous. It is only when embodied in actuality that a proof moves according to the anteriorposterior aspects of its logic. Validation is then the act by which the universe (qua logic) proves its consistency. Validation means "To attest to the observation of"  (my definition)In the case of the universe at large, some element (which is not functionally attached to a given interaction) must "observe" an interaction and attest to its validity by performing some action such as assuming a new state.
The difference between validation and existence is entirely semantic. So if I say, "Why must existence validate itself?", it is the same as saying "Why must existence exist?". And that answer is explored further along. Validation is then the identity of existence not a mere aspect of the case.
