In Einstein's theory of relativity the observer is a man who sets out in quest of truth armed with a measuring-rod. In quantum theory he sets out with a sieve.

Electrical force is defined as something which causes motion of electrical charge; an electrical charge is something which exerts electric force.

The electron, as it leaves the atom, crystallises out of Schrodinger's mist like a genie emerging from his bottle.

What is possible in the Cavendish Laboratory may not be too difficult in the sun.

It is a primitive form of thought that things exist or do not exist.

The physical world is entirely abstract and without actuality apart from its linkage to consciousness.

We used to think that if we knew one, we knew two, because one and one are two. We are finding that we must learn a great deal more about 'and'.