  Feynman famously recommended accepting the basic principles of quantum
mechanics without trying to guess the machinery behind the law. One of the
corollaries of the Uncertainty Principle is that the knowledge of probability
amplitudes does not allow one to make meaningful statements about the past of
an unobserved quantum system. A particular type of reasoning, based on weak
values, appears to do just that. Has Feynman been proven wrong by the more
recent developments? Most likely not.

Quantum Physics