Thus, the more precisely the position is determined, the less precisely the momentum is known, and conversely.

Many people will tell you that an expert is someone who knows a great deal about the subject. To this I would object that one can never know much about any subject. I would much prefer the following definition: an expert is someone who knows some of the worst mistakes that can be made in the subject, and how to avoid them.

Quantum theory provides us with a striking illustration of the fact that we can fully understand a connection though we can only speak of it in images and parables.

Can quantum mechanics represent the fact that an electron finds itself approximately in a given place and that it moves approximately with a given velocity, and can we make these approximations so close that they do not cause experimental difficulties?

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

Every tool carries with it the spirit by which it has been created.

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