Since we all partake of the global economy, we should have stuck together in trying to save it. We did not. The American central bank cut interest rates to 2 percent. The European central bank kept them twice as high, at 4 percent. The Japanese seemed most intent on saving their exports by ensuring that the yen did not rise against the dollar.

Even the Europeans could not stick together. The French proposed a joint European rescue fund of 300 billion euros (almost $500 billion) to guarantee all Europe's banks. The Germans, suspecting that their banks were richer and stronger than those of Italy and Spain and would thus bear the main burden, said no.

The Irish, who have long benefited financially from European solidarity even while keeping their corporate taxes seductively low at one-third of the average EU level, this week decided to save their own banks even if meant destabilizing the EU banking system.

Faced with a run on their banks, the Irish government gave a taxpayer guarantee to all deposits in Irish banks. Barely pausing to rub their eyes in disbelief, British, German, Dutch and other investors caused runs on their own domestic banks by scooping out money to transfer it into Irish banks.

As a world, we are not behaving well. The one area where there has been coordination, in pumping unprecedented amounts of central bank liquidity into the market. This week the Fed made an additional $630 billion available through its various lending facilities, following a $500 billion increase in the previous two weeks. It hasn't worked. The banks just sit on the money, not daring to lend.

The International Monetary Fund has been making very discreet soundings of major creditor countries, which means China, India, Taiwan, South Korea, Singapore, Saudi Arabia and the Gulf states to assess the prospects for some concerted international action. But everyone asks first what the Chinese intend to do, and the Chinese are stalling because they have not yet reached a consensus.

The Americans are not encouraging this talk of concerted international action party because they do not like the idea of policy being set by others and party because they know it would be the last shot in the world's locker.

In our arrogance, we have told ourselves that these days we know what caused the Wall Street crash of 1929 and the Great Depression of the 1930s, and so we know how to avoid repeating such a fate. Not so. We have re-learned that old and expensive lesson of history, that all we ever learn from the mistakes of the past is how to make new ones.