It would be asking a lot of an ordinary mortal to hew to the literal truth in a mortgage application when, to the applicant, it seemed as if the money was being offered free. And for 12 full months, from mid-2003 to mid-2004, the Fed set its interest rate, the so-called overnight federal funds rate, at just 1 percent. It took this extraordinary step to ward off the risk of falling prices, or deflation, it said. It would not tolerate too little inflation, it explained, but wanted just enough. At the time, the cost of living was rising by 2 percent a year.

Last week, as the Fed delivered its emergency cut of three-quarters of 1 percent, dropping the funds rate to 3.5 percent, the cost of living was rising on the order of 4 percent a year. Yet inflation was almost an afterthought in the press release in which the Federal Open Market Committee, the central bank’s policy-making arm, explained its surprise intervention: “The committee expects inflation to moderate in coming quarters, but it will be necessary to continue to monitor inflation developments carefully.”

If stability leads to instability, it follows that instability will eventually restore tranquillity. But first must come the tallying up of the errors, misjudgments and outright criminality that blossomed during the Great Moderation. Mr. Bernanke, in an attempt to limit the damage and hasten the healing, is likely to keep the Fed’s rate low  lower, even, than the measured inflation rate.

As for mortgages, the experts had agreed that house prices couldn’t fall as stock prices sometimes do, and they structured their loans without a thought to any such coast-to-coast distress. If house prices do continue to fall, there will be many more defaults, and a correspondingly urgent cry for low and lower mortgage rates.

Nor will the credit crisis bypass corporate America. Complacent as the mortgage lenders, investment bankers designed balance sheets as if steep and prolonged recession was not just unlikely but impossible.

To lubricate the machinery of lending and borrowing, Mr. Bernanke is likely to make dollars increasingly plentiful. The trouble is that, while the Fed is America’s central bank, the dollar is the world’s currency. It lines the vaults of central banks of America’s creditors, especially the up-and-coming states of Asia and the oil-soaked principalities of the Middle East.

Such institutions hold dollars by choice, and not a few of them chafe at the greenback’s steady loss of purchasing power. For some, Tuesday’s hasty rate cut might be the last straw.

As just about nobody predicted the present troubles, humility is what becomes today’s forecaster the most. So I will offer up a humble forecast. Inflation will, at length, make its way up from the bottom of the Fed’s worry list to the very top. Not for years has it seemed to matter that the dollar is only a piece of paper. But, before very long, that homely fact will push itself back to the fore.