It is no small art to sleep: for that purpose you must keep awake all day.
Man once surrendering his reason, has no remaining guard against absurdities the most monstrous, and like a ship without rudder, is the sport of every wind.
Anything that gives us new knowledge gives us an opportunity to be more rational.
The educated differ from the uneducated as much as the living differ from the dead.
The test of a first rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.
The whole difference between construction and creation is exactly this: that a thing constructed can only be loved after it is constructed; but a thing created is loved before it exists.
What could an entirely rational being speak of with another entirely rational being?
Somewhere, something incredible is waiting to be known.
Study without desire spoils the memory, and it retains nothing that it takes in.
I strongly believe that fundamental science cannot be driven by instructional, industrial and government or military pressures.