“Prediction is very difficult, especially about the future.”

“An expert is a person who has made all the mistakes that can be made in a very narrow field.”

“An expert is a man who has made all the mistakes which can be made in a very narrow field.”

“The very nature of the quantum theory ... forces us to regard the space-time coordination and the claim of causality, the union of which characterizes the classical theories, as complementary but exclusive features of the description, symbolizing the idealization of observation and description, respectively.”

“There are some things so serious that you have to laugh at them.”

“Never express yourself more clearly than you are able to think”

“There are trivial truths and there are great truths. The opposite of a trivial truth is plainly false. The opposite of a great truth is also true.”