But in this sort of a case, science does not take you far enough, says Mr. Heilbroner, an economics historian at the New School for Social Research.

These are questions that science cannot address but economics must, says Mark Blaug, an economics historian.

"In a situation that is perilously close to anarchy, these guys are taking wild risks," said Robert Heilbroner, the economics historian.

A economics historian, Mr. Hacker was also the author of a dozen books on American history.

"The I.M.F. formula could easily go wrong; in fact it is hard to make it go right," said Robert Heilbroner, an economics historian.

But some economists, like Robert Heilbroner, the economics historian, or Edward Yardeni, chief economist at Prudential-Bache, question whether the day of reckoning will ever arrive.

"There is something about the nature of economics training that is driving off the student," Mark Blaug, an economics historian, said in a recent interview.

"The last four years really have lifted our hopes about what is possible," said Paul Romer, an economics historian at Stanford University.

Ola Honningdal Grytten (born 30 May 1964) is a Norwegian economics historian.

"The fact this debate exists means no one knows who is right," said Robert Heilbroner, an economics historian who has written books with Mr. Thurow.