They are in you and me; they created us, body and mind; and their preservation is the ultimate rationale for our existence. They have come a long way, those replicators. Now they go by the name of genes, and we are their survival machines.

Natural selection is the blind watchmaker, blind because it does not see ahead, does not plan consequences, has no purpose in view. Yet the living results of natural selection overwhelmingly impress us with the appearance of design as if by a master watchmaker, impress us with the illusion of design and planning.

Each step is not too improbable for us to countenance, but when you add them up cumulatively over millions of years, you get these monsters of improbability, like the human brain and the rain forest. It should warn us against ever again assuming that because something is complicated, God must have done it.

Such is the breathtaking speciesism of our Christian-inspired attitudes, the abortion of a single human zygote can arouse more moral solicitude and righteous indignation than the vivasection of any number of intelligent adult chimpanzees! The only reason we can be comfortable with such a double standard is that the intermediates between humans and chimps are all dead.

If we want to postulate a deity capable of engineering all the organized complexity in the world, either instantaneously or by guiding evolution, that deity must have been vastly complex in the first place. The creationist, whether a naive Bible-thumper or an educated bishop, simply postulates an already existing being of prodigious intelligence and complexity. If we are going to allow ourselves the luxury of postulating organized complexity without offering an explanation, we might as well make a job of it and simply postulate the existence of life as we know it!

Yes, testosterone-sodden young men too unattractive to get a woman in this world might be desperate enough to go for 72 private virgins in the next.

Peter Sutcliffe, the Yorkshire Ripper, distinctly heard the voice of Jesus telling him to kill women, and he was locked up for life. George W. Bush says that God told him to invade Iraq (a pity God didn't vouchsafe him a revelation that there were no weapons of mass destruction).