After being open only an hour, the stock market has plunged catastrophically again. Whether or not this collapse will continue throughout the day, or whether it will reverse direction again in s few hours or days is anyone’s guess. They call this “volatility”, but that tells us nothing. When Moliere’s Dr Pangloss was asked why opium put people to sleep he answered “It possesses a dormative faculty.”

I can think of a variety of reasons, both real or imagined, why stock prices should go up or down. But that does not explain why, after a period of consistent and steady growth, they should suddenly start to oscillate erratically–and violently.

The Dow, like the summer ice extent in the Arctic Ocean, varies in the short term due to unpredictable local conditions. But what is driving the overall, long-term trend?