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.

You can't sit on two chairs at once.

Intellectual freedom is essential -- freedom to obtain and distribute information, freedom for open-minded and unfearing debate and freedom from pressure by officialdom and prejudices. Such freedom of thought is the only guarantee against an infection of people by mass myths, which, in the hands of treacherous hypocrites and demagogues, can be transformed into bloody dictatorship.

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.

Both now and for always, I intend to hold fast to my belief in the hidden strength of the human spirit.

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

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.