When asked ... [about] an underlying quantum world, Bohr would answer, 'There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about Nature.'

If you think you understand it, that only shows that you don't know the first thing about it.

The opposite of every great idea is another great idea.

In the great drama of existence we are audience and actors at the same time.

Prediction is very difficult, especially if it's about the future.

The old saying of the two kinds of truth. To the one kind belongs statements so simple and clear that the opposite assertion obviously could not be defended. The other kind, the so-called 'deep truths', are statements in which the opposite also contains deep truth.

One must always do what one really cannot.