We often think that when we have completed our study of one we know all about two, because 'two' is 'one and one.' We forget that we have still to make of a study of 'and.'

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.

Proof is the idol before whom the pure mathematician tortures himself.

We often think that when we have completed our study of one we know all about two, because "two" is "one and one." We forget that we still have to make a study of "and."

If an army of monkeys were strumming on typewriters, they might write all the books in the British Museum.

Science is one thing, wisdom is another. Science is an edged tool, with which men play like children, and cut their own fingers.

Not only is the universe stranger than we imagine, it is stranger than we can imagine.

Something unknown is doing we don't know what.

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'.

I ask you to look both ways. For the road to a knowledge of the stars leads through the atom; and important knowledge of the atom has been reached through the stars.

We have found a strange footprint on the shores of the unknown. We have devised profound theories, one after another, to account for its origins. At last, we have succeeded in reconstructing the creature that made the footprint. And lo! It is our own.

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

The mathematics is not there till we put it there.

It is impossible to trap modern physics into predicting anything with perfect determinism because it deals with probabilities from the outset.

Life would be stunted and narrow if we could feel no significance in the world around us beyond that which can be weighed and measured with the tools of the physicist or described by the metrical symbols of the mathematician.

We are bits of stellar matter that got cold by accident, bits of a star gone wrong.

When told that only 3 men in the world understood Relativity, Eddington asked "I wonder who is the third?"