Imagination without knowledge may create beautiful things, knowledge without imagination can create only perfect ones.

There is not the slightest indication that nuclear energy will ever be obtainable. It would mean that the atom would have to be shattered at will.

It is a very grave mistake to think that the enjoyment of seeing and searching can be promoted by means of coercion and a sense of duty. To the contrary, I believe it would be possible to rob even a healthy beast of prey of its voraciousness, if it were possible, with the aid of a whip, to force the beast to devour continuously, even when not hungry.

The only justification for our concepts and systems of concepts is that they serve to represent the complex of our experiences; beyond this they have not legitimacy.

Betterment of conditions the world over is not essentially dependent on scientific knowledge but on the fulfillment of human traditions and ideals.

Dostoevsky gives me more than any scientist, more than Gauss.

We can't solve today's problems with the mentality that created them.