Science is not formal logic-it needs the free play of the mind in as great a degree as any other creative art. It is true that this is a gift which can hardly be taught, but its growth can be encouraged in those who already posses it.

The belief that there is only one truth and that oneself is in possession of it seems to me the deepest root of all evil that is in the world.

If alpha [the fine-structure constant] were bigger than it really is, we should not be able to distinguish matter from ether [the vacuum, nothingness], and our task to disentangle the natural laws would be hopelessly difficult. The fact however that alpha has just its value 1/137 is certainly no chance but itself a law of nature. It is clear that the explanation of this number must be the central problem of natural philosophy.

Intellect distinguishes between the possible and the impossible; reason distinguishes between the sensible and the senseless. Even the possible can be senseless.

During my span of life science has become a matter of public concern and the l'art pour l'art standpoint of my youth is now obsolete. Science has become an integral and most important part of our civilization, and scientific work means contributing to its development. Science in our technical age has social, economic, and political functions, and however remote one's own work is from technical application it is a link in the chain of actions and decisions which determine the fate of the human race. I realized this aspect of science in its full impact only after Hiroshima.

Something which is against natural laws seems to me rather out of the question because it would be a depressive idea about God. It would make God smaller than he must be assumed. When he stated that these laws hold, then they hold, and he wouldn't make exceptions. This is too human an idea. Humans do such things, but not God.

All attempts to adapt our ethical code to our situation in the technological age have failed.