[Locke1689]

Actually that's only possible for one case -- a proof by counterexample. If, hypothetically, one were to prove that P=NP and only that an algorithm exists to solve NP-complete problems in P time, then that might be verifiable. However, even if that were the case, what if it turns out that the P-time algorithm complexity were O(n^100,000). That would be P-time, but not easily run for large NP-complete problems.