Something unknown is doing we don't know what.

Who will observe the observers?

Oh leave the Wise our measures to collate. One thing at least is certain, light has weight. One thing is certain and the rest debate. Light rays, when near the Sun, do not go straight.

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.

We have found that where science has progressed the farthest, the mind has but regained from nature that which the mind put into nature.

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'.

If your theory is found to be against the second law of theromodynamics, I give you no hope; there is nothing for it but to collapse in deepest humiliation.

Every body continues in its state of rest or uniform motion in a straight line, except insofar as it doesn't.

It is also a good rule not to put overmuch confidence in the observational results that are put forward until they are confirmed by theory.

It is even possible that laws which have not their origin in the mind may be irrational, and we can never succeed in formulating them.

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

It is sound judgment to hope that in the not too distant future we shall be competent to understand so simple a thing as a star.

Probably the simplest hypothesis... is that there may be a slow process of annihilation of matter.

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

Shuffling is the only thing which Nature cannot undo.

The mathematics is not there till we put it there.

The quest of the absolute leads into the four-dimensional world.

We have found a strange footprint on the shores of the unknown.

It is one thing for the human mind to extract from the phenomena of nature the laws which it has itself put into them; it may be a far harder thing to extract laws over which it has no control.