I want a man who knows something about himself. And is appalled. And has to forgive himself to get along.

It takes a very strong head to keep secrets for years and not go slightly mad. It isn't wise to be advised by anyone slightly mad.

Most of the scientists I have known well have felt - just as deeply as the non-scientists I have known well - that the individual condition of each is tragic. Each of us is alone: sometimes we escape from solitariness, through love or affection or perhaps creative moments, but those triumphs of life are pools of light we make for ourselves while the edge of the road is black: each of us dies alone.

This ability to incorporate the past gives the sharpest diagnostic tool, if one asks whether a body of knowledge is a science or not. Do present practitioners have to go back to an original work of the past? Or has it been incorporated? ... Science is cumulative, and embodies its past.

If you pursue happiness you never find it.

Civilization is hideously fragile... there's not much between us and the Horrors underneath, just about a coat of varnish.

The main issue [of the Scientific Revolution] is that the people in the industrialised countries are getting richer, and those in the non-industrialised countries are at best standing still: so the gap between the industrialised countries and the rest is widening every day. On the world scale this is the gap between the rich and the poor.