My belief, for what it is worth, is that city dwellers cannot understand the world. Insulated from reality by complex and expert systems of provision and police, baffled by fashion and spectacle, city dwellers can distinguish neither the sources of their existence nor the consequences.

There are signs that the age of petroleum has passed its zenith. Adjusted for inflation, a barrel of crude oil now sells for three times its long-run average. The large western oil companies, which cartellised the industry for much of the 20th century, are now selling more oil than they find, and are thus in the throes of liquidation.

Profits in business always depend on the rate of interest: the higher the interest, the higher the rate of profit required.

The year 2008 was a reminder to those who had forgotten that there is such a thing as history and that the cycle of famine and feast in commerce, first identified in antiquity and well understood in the Middle Ages, was not suddenly abolished in modern times.

One of the consequences of the Iranian revolution has been an explosion of history. A country once known only from British consular reports and intrepid travelogues is now awash with historical documents, letters, diaries, grainy video, weblogs and secret police files of questionable authenticity.

Were there peace and justice in the Middle East, the Arabs would no more need their tinhorn dictators than they would their corpulent princes.

The use of refined petroleum as fuel, which began in the 1850s, freed hundreds of millions of people from the toil of centuries, gave hundreds of millions more a life of ease and plenty, and, by allowing great cities to feed themselves from every corner of the world, multiplied the population of the earth fivefold.