Wars are times of intense technological transformation, because societies invest - sometimes with extensive borrowing - when and where matters of life and death are at stake.

Italy is the fourth-largest economy in Europe and the eighth-largest economy in the world, and its banking system is collapsing. And Germany is desperate. It must maintain its standard of living. It can only do that with exports and Deutsche Bank is very exposed to Italian debt. But so is the rest of Europe.

War and sex are what I call the two abysmal - by that I mean deep - parts of the human condition.

Constraint theory asks: What is the price for doing this? Now one way around constraint theory is declaring your enemy crazy. Crazy and stupid are not concepts used in forecasting. When people say they're really stupid or they're crazy, that's laziness. That means I don't want to think through their position or about what they're really going to do.

The most horrible sort of war is civil war.

What is the great fear of the United States? That an Eastern power will build a navy to challenge us. How do you keep them from doing that? Keep them at each other's throats so they don't have any money to do this. This is why we fought the First World War, the Second World War, and the Cold War.

By the 20th century, war ceased to be an encounter between two armies. It became an encounter between two societies, because a factory worker producing a gun or a bomb is as deadly as a pilot.