Society works not because we have consciously invented it, but because it is an ancient product of our evolved predispositions. It is literally in our nature.

Simple determinism, whether of the genetic or environmental kind, is a depressing prospect for those with a fondness for free will.

The interaction of genetic and external influences makes my behaviour unpredictable, but not undetermined. In the gap between those words lies freedom.

In a massive, long-term study of 17,000 civil servants, an almost unbelievable conclusion emerged: the status of a person's job was more likely to predict their likelihood of a heart attack than obesity, smoking or high blood pressure.

The message from history is so blatantly obvious - that free trade causes mutual prosperity while protectionism causes poverty - that it seems incredible that anybody ever thinks otherwise. There is not a single example of a country opening its borders to trade and ending up poorer.

Ecology, like genetics, is not about equilibrium states. It is about change, change and change. Nothing stays the same forever.

How much more generous it would be if, instead of writing parables about childhood wounds, psychologists were to accept that some differences between the sexes just are, that they are in the nature of the beasts, because each sex has an evolved tendency to develop that way in response to experience.