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

No rational argument will have a rational effect on a man who does not want to adopt a rational attitude.

The growth of our knowledge is the result of a process closely resembling what Darwin called 'natural selection'; that is, the natural selection of hypotheses: our knowledge consists, at every moment, of those hypotheses which have shown their (comparative) fitness by surviving so far in their struggle for existence, a competitive struggle which eliminates those hypotheses which are unfit.

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

Science may be described as the art of systematic over-simplification.

No book can ever be finished. While working on it we learn just enough to find it immature the moment we turn away from it

Our aim as scientists is objective truth; more truth, more interesting truth, more intelligible truth. We cannot reasonably aim at certainty. Once we realize that human knowledge is fallible, we realize also that we can never be completely certain that we have not made a mistake.