The fact that Newton and Michael Faraday and other scientists of the past were deeply religious shows that religious skepticism is not a prejudice that governed science from the beginning, but a lesson that has been learned through centuries of experience in the study of nature.

A theorist today is hardly considered respectable if he or she has not introduced at least one new particle for which there is no experimental evidence.

In science we don't have prophets. We have heroes, but not prophets.

If history is any guide at all, it seems to me to suggest that there is a final theory. In this century we have seen a convergence of the arrows of explanation, like the convergence of meridians toward the North Pole.

As for me, I have just enough confidence about the multiverse to bet the lives of both Andrei Linde and Martin Rees’s dog.

My advice is to go for the messes - that's where the action is.

I now want to tell three stories about advances in twentieth-century physics. A curious fact emerges in these tales: time and again physicists have been guided by their sense of beauty not only in developing new theories but even in judging the validity of physical theories once they are developed. Simplicity is part of what I mean by beauty, but it is a simplicity of ideas, not simplicity of a mechanical sort that can be measured by counting equations or symbols.