Bulls don't read. Bears read financial history. As markets fall to bits, the bears dust off the Dutch tulip mania of 1637, the Banque Royale of 1719-20, the railway speculation of the 1840s, the great crash of 1929.

Cause and effect, the riddle of all history, is a particular devil in financial history and never more so than today, where entire classes of security are collapsing not on public exchanges and stock-tickers but because there are no markets to establish prices this side of nothing.

For all their current prestige, Osama bin Laden and the suicide bombers are still regarded in all but the most desperate districts of Gaza or Peshawar as romantics with little chance of more than symbolic victories, however bloody and brutal. That gives both the Middle East and the West a small and distant hope of security.

In rising financial markets, the world is forever new. The bull or optimist has no eyes for past or present, but only for the future, where streams of revenue play in his imagination.

Because bankers measure their self-worth in money, and pay themselves a lot of it, they think they're fine fellows and don't need to explain themselves.