One thought spectra are marvellous, but it is not possible to make progress there. Just as if you have the wing of a butterfly then certainly it is very regular with the colors and so on, but nobody thought one could get the basis of biology from the coloring of the wing of a butterfly.

What is that we human beings ultimately depend on? We depend on our words. We are suspended in language. Our task is to communicate experience and ideas to others.

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.'

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

Anybody who is not shocked by this subject has failed to understand it. [of quantum mechanics]

Never express yourself more clearly than you are able to think.

Anyone not shocked by quantum mechanics has not yet understood it.