Prediction is very difficult, especially about the future. - Niels Bohr

"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."

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

"The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth."

"The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth."

"How wonderful that we have met with a paradox. Now we have some hope of making progress."