There’s also, one has to say, an element of wishful thinking here. For whatever reason, many people in the financial industry have developed a deep hatred for Ben Bernanke, the Fed chairman, and everything he does; they want his easy-money policies ended, and they also want to see those policies fail in some spectacular fashion. As it turns out, however, dislike for bearded Princeton professors is not a good basis for investment strategy.

And one should never forget the example of Japan, where bets against government bonds — justified by more or less the same arguments currently made to justify claims of a U.S. bond bubble — ended in grief so often that the whole trade came to be known as the “widow maker.” At this point, Japan’s debt is well over twice its G.D.P., its budget deficit remains large, and the interest rate on 10-year bonds is 0.6 percent. No, that’s not a misprint.

O.K., what about stocks? Major stock indexes are now higher than they were at the end of the 1990s, which can sound ominous. It sounds a lot less ominous, however, when you learn that corporate profits — which are, after all, what stocks are shares in — are more than two-and-a-half times higher than they were when the 1990s bubble burst. Also, with bond yields so low, you would expect investors to move into stocks, driving their prices higher.

All in all, the case for significant bubbles in stocks or, especially, bonds is weak. And that conclusion matters for policy as well as investment.

For one important subtext of all the recent bubble rhetoric is the demand that Mr. Bernanke and his colleagues stop trying to fight mass unemployment, that they must cease and desist their efforts to boost the economy or dire consequences will follow. In fact, however, there isn’t any case for believing that we face any broad bubble problem, let alone that worrying about hypothetical bubbles should take precedence over the task of getting Americans back to work. Mr. Bernanke should brush aside the babbling barons of bubbleism, and get on with doing his job.