My practise as a scientist is atheistic. That is to say, when I set up an experiment I assume that no god, angel, or devil is going to interfere with its course; and this assumption has been justified by such success as I have achieved in my professional career. I should therefore be intellectually dishonest if I were not also atheistic in the affairs of the world. And I should be a coward if I did not state my theoretical views in public.

Would I lay down my life to save my brother? No, but I would to save two brothers or eight cousins.

We do not know, in most cases, how far social failure and success are due to heredity, and how far to environment. But environment is the easier of the two to improve.

I have never yet met a healthy person who worried very much about his health, or a really good person who worried much about his own soul.

I think, however, that so long as our present economic and national systems continue, scientific research has little to fear.

It was a reaction from the old idea of "protoplasm", a name which was a mere repository of ignorance.

Science is as yet in its infancy, and we can foretell little of the future save that the thing that has not been is the thing that shall be; that no beliefs, no values, no institutions are safe.