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'.

In any attempt to bridge the domains of experience belonging to the spiritual and the physical sides of our nature, time occupies the key position.

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

He who doubts the reality of the four-dimensional world (for logical, as distinct from experimental, reasons) can only be compared to a man who doubts the reality of the penny, and prefers to regard one of its innumerable appearances as the real object.

Clearly a statement cannot be tested by observation unless it is an assertion about the results of observation. Every item of physical knowledge must therefore be an assertion of what has been or would be the result of carrying out a specified observational procedure.

Reality is only obtained when all conceivable points of view have been combined.

Something unknown is doing we don't know what.

The ultimate elements in a theory of the world must be of a nature impossible to define in terms recognizable to the mind.

What we are observing is not nature herself, but nature exposed to our type of question.

It is a good rule not to put overmuch confidence in a theory until it has been confirmed by observation. I hope I shall not shock the experimental physicists too much if I add that it is also a good rule not to put overmuch confidence in the observational results that are put forward until they have been confirmed by theory.