The mathematics is not there till we put it there.

The man in the street is always making this demand for concrete explanation of the things referred to in science; but of necessity he must be disappointed. It is like our experience in learning to read. That which is written in a book is symbolic of a story in real life.

Our knowledge of things where we are not, and of things when we are not, is essentially the same -- an inference (sometimes a mistaken inference) from brain impressions, including memory, here and now.

Common sense is the collection of prejudices acquired by age eighteen.

All are lunatics, but he who can analyze his delusion is called a philosopher.

We are left with the indisputable but irritating conclusion: 0 = 0. This is a favourite device that mathematical equations resort to, when we propound stupid questions.

Science aims at constructing a world which shall be symbolic of the world of commonplace experience. It is not at all necessary that every individual symbol that is used should represent something in common experience or even something explicable in terms of common experience.

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

It was the experience of mystery - even if mixed with fear - that engendered religion.

Cogito cogito ergo cogito sum (I think that I think, therefore I think that I am.)