I invented nothing new, I simply assembled the discoveries of other men behind whom there was centuries of work.

My opposition to war is not based upon pacifist or non-resistant principles. It may be that the present state of civilization is such that certain international questions cannot be discussed; it may be that they have to be fought out. But the fighting never settles the question. It only gets the participants around to a frame of mind where they will agree to discuss what they were fighting about.

Money is like an arm or leg - use it or lose it.

Don't find fault, find a remedy.

The greatest thing in life is to keep your mind young.

The time will come when man will know even what is going on in the other planets and perhaps be able to visit them.

Thinking is the hardest work there is, which is probably the reason why so few engage in it.