Proof is an idol before which the mathematician tortures himself.

Something unknown is doing we don't know what-that is what our theory amounts to.

There was a time when we wanted to be told what an electron is. The question was never answered. No familiar conceptions can be woven around the electron; it belongs to the waiting list.

Unless the structure of the nucleus has a surprise in store for us, the conclusion seems plain-there is nothing in the whole system if laws of physics that cannot be deduced unambiguously from epistemological considerations. An intelligence, unacquainted with our universe, but acquainted with the system of thought by which the human mind interprets to itself the contents of its sensory experience, and should be able to attain all the knowledge of physics that we have attained by experiment.