Every word or concept, clear as it may seem to be, has only a limited range of applicability.

I believe that the existence of the classical "path" can be pregnantly formulated as follows: The "path" comes into existence only when we observe it.

Nature is made in such a way as to be able to be understood. Or perhaps I should put it-more correctly-the other way around, and say that we are made in such a way as to be able to understand Nature.

When I meet God, I am going to ask him two questions: Why relativity ? And why turbulence ? I really believe he will have an answer for the first.

The conception of objective reality ... has thus evaporated ... into the transparent clarity of mathematics that represents no longer the behavior of particles but rather our knowledge of this behavior.

The positivists have a simple solution: the world must be divided into that which we can say clearly and the rest, which we had better pass over in silence. But can anyone conceive of a more pointless philosophy, seeing that what we can say clearly amounts to next to nothing? If we omitted all that is unclear, we would probably be left completely uninteresting and trivial tautologies.

There are things that are so serious that you can only joke about them.