A person starts to live when he can live outside himself.

Education- That which discloses to the wise and disguises from the foolish their lack of understanding.

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.

The principles of logic and mathematics are true simply because we never allow them to be anything else.

In the end, it's not the years in your life that count. It's the life in your years.