I could not stop something I knew was wrong and terrible. I had an awful sense of powerlessness.

In and after 1964 when I began to concern myself with the biological issues, and particularly from 1967 onwards, the extent of the problems over which I felt uneasy increased to such a point that in 1968 I felt a compelling urge to make my views public.

I've always thought that the most powerful weapon in the world was the bomb and that's why I gave it to my people, but I've come to the conclusion that the most powerful weapon in the world is not the bomb but it's the truth

My present work concerns the problems connected with the theory of elementary particles, the theory of gravitation and cosmology and I shall be glad if I can manage to make some contribution to these important branches of science.

International affairs must be completely permeated with scientific methodology and a democratic spirit, with a fearless weighing of all facts, views, and theories, with maximum publicity of ultimate and intermediate goals, and with a consistency of principles.

For me, the moral difficulties lie in the continual pressure brought to bear on my friends and immediate family, pressure which is not directed against me personally but which at the same time is all around me.

In 1947 I defended my thesis on nuclear physics, and in 1948 I was included in a group of research scientists whose task was to develop nuclear weapons.