Pronouncement of experts to the effect that something cannot be done has always irritated me.

We turned the switch, saw the flashes, watched for ten minutes, then switched everything off and went home. That night I knew the world was headed for sorrow.

A great power imposes the obligation of exercising restraint, and we did not live up to this obligation. I think this affected many of the scientists in a subtle sense, and it diminished their desire to continue to work on the bomb.

When a scientist says something, his colleagues must ask themselves only whether it is true. When a politician says something, his colleagues must first of all ask, 'Why does he say it?

Do not destroy what you cannot create.

If one knows only what one is told, one does not know enough to be able to arrive at a well-balanced decision.

I am thinking of keeping a diary, not with the intend to publish it, merely to record the facts for the information of God, in case God does not know my version of the facts.