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.

If atomic bombs are to be added as new weapons to the arsenals of a warring world, or to the arsenals of nations preparing for war, then the time will come when mankind will curse the names of Los Alamos and Hiroshima. The people must unite, or they will perish.

The double horror of two Japanese city names [Hiroshima and Nagasaki] grew for me into another kind of double horror; an estranging awareness of what the United States was capable of, the country that five years before had given me its citizenship; a nauseating terror at the direction the natural sciences were going. Never far from an apocalyptic vision of the world, I saw the end of the essence of mankind an end brought nearer, or even made, possible, by the profession to which I belonged. In my view, all natural sciences were as one; and if one science could no longer plead innocence, none could.