In the run-up to this weekend's G-8 summit at Camp David, journalists have unfavorably compared European "austerity" with Barack Obama's economic policies.

A common fallacy holds that imposing taxes on imports and rebating taxes on exports would stimulate the economy.

From Mr Alex J. Pollock.

Sir, Jonathan Davis ("Watch that desire for certainty and elegance", FTfm, February 6) correctly addresses the danger of false certainty in economics, but concludes by quoting Keynes about how economic policy had "blundered...

Until recently there was wide consensus among macroeconomists that activist fiscal policy was inadvisable.

Although John Maynard Keynes died more than a half-century ago, his diagnosis of recessions and depressions remains the foundation of modern macroeconomics.

We have to face a key reality: Well-intentioned but disastrous mistakes are made by very intelligent, well-educated, highly informed people, backed by vast computing power and reams of data, but wrong nonetheless.

Economic change for the better has todo with a powerful boost from extra government spending, an idea Keynes pioneered, and from tax rate cuts, an idea pioneered by Ronald Reagan.

Perceptions of uncertain future events like credit safety or credit risk are inherently subjective and highly influenced by the views of all the others who are doing what you are doing.