Observation and theory get on best when they are mixed together, both helping one another in the pursuit of truth. 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.

There was a time when we wanted to be told what an electron is. The question was never answered. No familiar conceptions can be woven around the electron; it belongs to the waiting list.

In the most modern theories of physics probability seems to have replaced aether as "the nominative of the verb 'to undulate'."

Who will observe the observers?

In the world of physics we watch a shadowgraph performance of the drama of familiar life. The shadow of my elbow rests on the shadow table as the shadow ink flows over the shadow paper. It is all symbolic, and as a symbol the physicist leaves it. ... The frank realisation that physical science is concerned with a world of shadows is one of the most significant of recent advances.

Philosophically, the notion of a beginning of the present order of Nature is repugnant to me ... I should like to find a genuine loophole.

The understanding between a non-technical writer and his reader is that he shall talk more or less like a human being and not like an Act of Parliament. I take it that the aim of such books must be to convey exact thought in inexact language... he can never succeed without the co-operation of the reader.