In prehistoric times, Homo sapiens was deeply endangered. Early humans were less fleet of foot, with fewer natural weapons and less well-honed senses than all the predators that threatened them. Moreover, they were hampered in their movements by the need to protect their uniquely immature young - juicy meals for any hungry beast.

Religion has endured since the dawn of human consciousness precisely because it encompasses so much of being human. No idea has endured so long, gathered up so many disparate needs and wants and feelings, and inspired so many different paths towards understanding it.

Having a child is arguably the most important thing you do in life.

Women of child-bearing age steadily run out of eggs by the continuous process of cell death. While reading a copy of the Guardian carefully from cover to cover, a normal woman will have lost on average two eggs - while, typically, a normal man will have made 70,000 new sperm.

Surgeons always underestimate the pain and disability involved in what they do to people.

We are more dependent on science and engineering than at any other time in history. However, there is plenty of evidence that far too many people are scientifically illiterate, often having been put off science at school.

Our aggression is a deep instinct which survives in all kinds of manifestations in modern man.