In his classic "Fable of the Bees: or, Private Vices, Publick Benefits" (1724), Bernard Mandeville, the Dutch-born British philosopher and satirist, described a prosperous society (of bees) that suddenly chose to make a virtue of austerity.

What then happened?

The Price of Land and Houses falls...

Mirac'lous Palaces, whose Walls,

Like those of Thebes, were rais'd by Play

Are to be let; . . .

That sounds a lot like what many advanced countries have been going through, after financial-crisis-induced austerity plans were launched, doesn't it?

Is Mandeville a genuine prophet for our times?

The austerity plans being adopted by governments in much of Europe and elsewhere around the world, and the curtailment of consumption expenditure by individuals as well, threaten to produce a global recession.

But how do we know if Mandeville is right about austerity? His research method - a long poem about his theory- is hardly convincing to modern ears.

Harvard economist Alberto Alesina recently summarized evidence concerning whether government deficit reduction - that is, expenditure cuts and/or tax increases- always induces such negative effects: "The answer to this question is a loud no."

Sometimes, even often, economies prosper nicely after the government's deficit is sharply reduced. Sometimes, just maybe, the austerity program boosts confidence in such a way as to ignite a recovery.

Jaime Guajardo, Daniel Leigh, and Andrea Pescatori of the International Monetary Fund recently studied austerity plans implemented by governments in 17 countries in the last 30 years.

But their approach differed from that of previous researchers. They focused on the government's intent, and looked at what officials actually said, not just at the pattern of public debt.

They identified as austerity plans only those cases in which governments imposed tax hikes or spending cuts because they viewed it as a prudent policy with potential long-term benefits, not because they were responding to the short-term economic outlook and sought to reduce the risk of overheating.

Their analysis found a clear tendency for austerity programs to reduce consumption expenditure and weaken the economy. That conclusion, if valid, stands as a stern warning to policymakers today.

But critics, such as Valerie Ramey of the University of California at San Diego, think that Guajardo, Leigh, and Pescatori have not completely proven their case.

Worrisome debt

It is possible, Ramey argues, that their results could reflect a different sort of reverse causality if governments are more likely to respond to high public-debt levels with austerity programs when they have reason to believe that economic conditions could make the debt burden especially worrisome.

Ramey could be right. One would then find that government spending cuts or tax hikes tend to be followed by bad economic times, even if the causality runs the other way.

Ultimately, the problem of judging austerity programs is that economists cannot run fully controlled experiments. When researchers tested Prozac on depressed patients, they divided their subjects randomly into control and experimental groups, and conducted many trials. We cannot do that with national debt.

So do we have to conclude that historical analysis teaches us no useful lessons? Do we have to return to the abstract reasoning of Mandeville and some of his successors, including John Maynard Keynes, who thought that there were reasons to expect that austerity would produce depressions?

There is no abstract theory that can predict how people will react to an austerity program. We have no alternative but to look at the historical evidence. And the evidence of Guajardo and his co-authors does show that deliberate government decisions to adopt austerity programs have tended to be followed by hard times.

Policymakers cannot afford to wait decades for economists to figure out a definitive answer, which may never be found at all. But, judging by the evidence that we have, austerity programs in Europe and elsewhere appear likely to yield disappointing results.