When time permits, I try to see interesting people in the cities I visit. In Seattle, I met Paul Allen, the co-founder of Microsoft, who is shy in personality but flamboyant in his philanthropy.

I try to jog in every city I visit, and I particularly enjoy harbour-front paths that let me ogle big ships, railroad bridges and the ruins of factories and warehouses.

You could think of an ecosystem as a bunch of antagonistic arms races, almost: Everything that an animal depends upon for food is the body part of some other animal or plant who would just as soon keep that body part for itself.

Commerce, trade and exchange make other people more valuable alive than dead, and mean that people try to anticipate what the other guy needs and wants. It engages the mechanisms of reciprocal altruism, as the evolutionary biologists call it, as opposed to raw dominance.

I have never been a fan of science fiction. For me, fiction has to explore the combinatorial possibilities of people interacting under the constraints imposed by our biology and history. When an author is free to suspend the constraints, it's tennis without a net.

When people talk, they lay lines on each other, do a lot of role playing, sidestep, shilly-shally and engage in all manner of vagueness and innuendo. We do this and expect others to do it, yet at the same time we profess to long for the plain truth, for people to say what they mean, simple as that. Such hypocrisy is a human universal.

Most wars are not fought over shortages of resources such as food and water, but rather over conquest, revenge, and ideology.