Take male strategies for success in the world. If you've got all the advantages, if you're attractive and clever and all of that, you will generally go for very high quality females.

Imagine a world full of brains, and far more memes than can possibly find homes. Which memes are more likely to find a safe home and get passed on again?

Science has, after all, made some colossal blunders in the past... Our current materialism and its rejection of the idea of a spirit or soul might be just another great falsity.

In proportion to our body mass, our brain is three times as large as that of our nearest relatives. This huge organ is dangerous and painful to give birth to, expensive to build and, in a resting human, uses about 20 per cent of the body's energy even though it is just 2 per cent of the body's weight. There must be some reason for all this evolutionary expense.

Finally, we might decide that civilisation itself is worth preserving. In that case we have to work out what to save and which people would be needed in a drastically reduced population - weighing the value of scientists and musicians against that of politicians, for example...

All other species on this planet are gene machines only. They don't imitate at all well; we alone are gene machines and meme machines as well.

'Temes' [technology-enhanced memes] don't care about us - they simply want to create more of themselves. Don't think we created the internet for our own benefit - think about temes spreading for themselves because they must.