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.

In my paper the fact the XY was not equal to YX was very disagreeable to me. I felt this was the only point of difficulty in the whole scheme...and I was not able to solve it.

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

The ontology of materialism rested upon the illusion that the kind of existence, the direct "actuality" of the world around us, can be extrapolated into the atomic range. This extrapolation is impossible, however.

Whenever we proceed from the known to the unkown we may hope to understand, but we may have to learn at the same time a new meaning of the word 'understanding'

Even for the physicist the description in plain language will be a criterion of the degree of understanding that has been reached.

What we observe is not nature itself but nature exposed to our method of questioning. Our scientific work in physics consists in asking questions about nature in the language that we possess and trying to get an answer from experiment by the means that are at our disposal.