Alas, Islam turned against science in the twelfth century. The most influential figure was the philosopher Abu Hamid al-Ghazzali, who argued in The Incoherence of the Philosophers against the very idea of laws of nature, on the ground that any such laws would put God's hands in chains. According to al-Ghazzali, a piece of cotton placed in a flame does not darken and smoulder because of the heat, but because God wants it to darken and smoulder. After al-Ghazzali, there was no more science worth mentioning in Islamic countries.

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.

It is almost irrestible for humans to believe that we have some special relation to the universe, that human life is not just a more-or-less farcical outcome of a chain of accidents reaching back to the first three minutes, but that we were somehow built in from the beginning.

It seems that scientists are often attracted to beautiful theories in the way that insects are attracted to flowers — not by logical deduction, but by something like a sense of smell.

The more we refine our understanding of God to make the concept plausible, the more it seems pointless.

With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion.

The invisible and the non-existent look very much alike.