Asked in 1919 whether it was true that only three people in the world understood the theory of general relativity, [Eddington] allegedly replied: "Who's the third?"

Never accept a fact until it has been verified by theory.

We have found that where science has progressed the farthest, the mind has but regained from nature that which the mind put into nature.

Electrical force is defined as something which causes motion of electrical charge; an electrical charge is something which exerts electric force.

I ask you to look both ways. For the road to a knowledge of the stars leads through the atom; and important knowledge of the atom has been reached through the stars.

If your theory is found to be against the second law of thermodynamics I give you no hope; there is nothing for it but to collapse in deepest humiliation.

What we makes of the world must be largely dependent on the sense-organs that we happen to possess. How the world must have changed since the man came to rely on his eyes rather than his nose.