It seems sensible to discard all hope of observing hitherto unobservable quantities, such as the position and period of the electron... Instead it seems more reasonable to try to establish a theoretical quantum mechanics, analogous to classical mechanics, but in which only relations between observable quantities occur.

Looking at something changes it.

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

The basic idea is to shove all fundamental difficulties onto the neutron and to do quantum mechanics in the nucleus.

The Same organizing forces that have shaped nature in all her forms are also responsible for the structure of our minds.

The violent reaction on the recent development of modern physics can only be understood when one realises that here the foundations of physics have started moving; and that this motion has caused the feeling that the ground would be cut from science

The one who insists on never uttering an error must remain silent.