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.'

You must come to Copenhagen to work with us. We like people who can actually perform thought experiments!

There are some things so serious you have to laugh at them.

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.

It is very difficult to make an accurate prediction, especially about the future.

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

Predictions are hard, especially abot the future.