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.

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

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.

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.

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.

Profound insights arise only in debate, with a possibility of counterargument, only when there is a possibility of expressing not only correct ideas but also dubious ideas.

Intellectual freedom is the only guarantee of a scientific - democratic approach to politics, economic development, and culture.