It is going to be necessary that everything that happens in a finite volume of space and time would have to be analyzable with a finite number of logical operations. The present theory of physics is not that way, apparently. It allows space to go down into infinitesimal distances, wavelengths to get infinitely great, terms to be summed in infinite order, and so forth; and therefore, if this proposition [that physics is computer-simulatable] is right, physical law is wrong.

For those who want some proof that physicists are human, the proof is in the idiocy of all the different units which they use for measuring energy.

Mathematics is not just a language. Mathematics is a language plus reasoning.

The real problem in speech is not precise language. The problem is clear language.

Some people think Wheeler's gotten crazy in his later years, but he's always been crazy.

Know how to solve every problem that has been solved.

There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time ... On the other hand, I think I can safely say that nobody understands quantum mechanics.