Nature consists of facts and of regularities, and is in itself neither moral nor immoral. It is we who impose our standards upon nature, and who in this way introduce morals into the natural world, in spite the fact that we are part of this world. We are products of nature, but nature has made us together with our power of altering the world, of foreseeing and of planning for the future, and of making far-reaching decisions for which we are morally responsible. Yet, responsibility, decisions, enter the world of nature only with us

Science is perhaps the only human activity in which errors are systematically criticized and, in time, corrected.

The defence of democracy must consist in making anti-democratic experiences too costly for those who try them; much more costly than a democratic compromise

A system such as classical mechanics may be 'scientific' to any degree you like; but those who uphold it dogmatically - believing, perhaps, that it is their business to defend such a successful system against criticism as long as it is not conclusively disproved - are adopting the very reverse of that critical attitude which in my view is the proper one for the scientist.

The moral decisions of others should be treated with respect, as long as such decisions do not conflict with the principle of tolerance.

The conspiracy theory of society... comes from abandoning god and then asking: "Who is in his place"

Piecemeal social engineering resembles physical engineering in regarding the ends as beyond the province of technology.