Suffering is a byproduct of evolution by natural selection, an inevitable consequence that may worry us in our more sympathetic moments but cannot be expected to worry a tiger - even if a tiger can be said to worry about anything at all - and certainly cannot be expected to worry its genes.

We are machines built by DNA whose purpose is to make more copies of the same DNA. ... This is exactly what we are for. We are machines for propagating DNA, and the propagation of DNA is a self-sustaining process. It is every living object's sole reason for living.

The total amount of suffering per year in the natural world is beyond all decent contemplation. During the minute that it takes me to compose this sentence, thousands of animals are being eaten alive, many others are running for their lives, whimpering with fear, others are slowly being devoured from within by rasping parasites, thousands of all species are dying of starvation, thirst, and disease. The universe that we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but pitiless indifference.

The take-home message is that we should blame religion itself, not religious extremism - as though that were some kind of terrible perversion of real, decent religion. Voltaire got it right long ago: 'Those who can make you believe absurdities can make you commit atrocities.' So did Bertrand Russell: 'Many people would sooner die than think. In fact they do.

Show me a cultural relativist at 30,000 feet and I'll show you a hypocrite ... If you are flying to an international congress of anthropologists or literary critics, the reason you will probably get there - the reason you don't plummet into a ploughed field - is that a lot of Western scientifically trained engineers have got their sum right.

Do you really mean to tell me the only reason you try to be good is to gain God's approval and reward, or to avoid his disapproval and punishment? That's not morality, that's just sucking up, apple-polishing, looking over your shoulder at the great surveillance camera in the sky, or the still small wiretap inside your head, monitoring your every move, even your every base though.

It is universally accepted that an admission of atheism would be instant political suicide for any (U.S.) presidential candidate.