Let the recession last another six months and the merchants of economic prophecy in this city might begin looking into the east wind for flights of symbolic geese. The customary methods of divination have failed so miserably since the advent of Ronald Reagan that any economist who offers to project the course of the market exposes himself to ridicule.

The older practitioners of the art, of course, show no signs of shame, apology or embarrassment. So many of their predictions have been proved so wrong for so many years that they have become impervious to the judgments of experience. They continue to advise presidents, to serve as consultants to corporations, to receive Nobel prizes and honorary degrees, to smile and bow and calmly say that before the year is out the price of gold will stand, depending on their temperament, at either $50 or $2,000 an ounce. Having learned to fit their vision of the future to the specifications of the audience to which the vision is revealed, they whisper into the ears of their patrons the news their patrons pay to hear.

Some of the younger prophets haven't yet developed the necessary "sangfroid." Troubled by self-doubt and wondering whether they truly possess the gift of seeing into the mists of tomorrow afternoon, they still worry about the discrepancy between what happens and what they have said will happen.

On Tuesday of this week I ran across one of these apprentice seers at a seminar convened by a public-spirited bank. The young man, G. Ragsdale Witherspoon, had been invited to speak about the coming to pass of higher interest rates and the wisdom of buying Treasury bills and tax-exempt bonds. On Monday, the stock market had staged an impressive rally, the Dow Jones industrial average gaining 10.75 points on a volume of nearly 75 million shares, and by the time Witherspoon reached the podium he wished that he had brought a different set of slides.

The experience unnerved him. A few hours later, thoughtfully considering his options in the hotel bar, he went so far as to question the infallibility of his charts and statistical averages.

"What good are the computers?" he said. "What's the point of all the numbers if I can't find out what they mean?"

He had been reading about the art of divination as it was practiced by the augurs in ancient Rome, and it occurred to him to try omens that had nothing to do with M1 or Standard and Poor's index.

"Suppose," he said, "I attach the data base to weird signs and portents. You know the sort of thing I mean-- birds arriving from the left, mice gnawing at the statue of Alexander Hamilton, the number of cocaine dealers found floating in the East River on the night of the autumnal equinox."

The thought revived his spirit, and within an hour he had sketched out a newsletter entitled "Witherspoon's Algorithms." He made a list of 99 key indicators (the number equivalent to the Muslim names of God) and these he proposed to publish every week in the form of a scroll. The trick, he said, would be to make the indicators both as specific and as obscure as possible, thus endowing them with an aura of unutterable significance. He showed me the entire list, but I only had time to copy down on a paper napkin the ones that struck me as the most relevant:

* barrels of oil spilled on the beach in Santa Monica

* wars broken out south of the 38th parallel

* Broadway shows closed

* bushels of corn sent to China

* ransoms (known) paid by Saudi Arabian princes

* newspapers sold to the Newhouse organization

* grants awarded to ballet companies in North Carolina

* mice cloned

* inflation rate in Argentina

* politicians (federal) currently under indictment

* barrels of perfume imported into Atlantic City

* currencies devalued by more than 30 percent

* votes taken in Uganda

* characters (female) killed on prime time television

* average age of the Politburo

* missile systems sold to Spanish-speaking dictators

* prostitutes (male) arrested in Minneapolis

* public executions in Tehran

* books proscribed in central Ohio

* outrages committed against members of the United States Senate

* actors drowned at sea

By adding all the numbers in the algorithm, Witherspoon would arrive at a mystical sum representing the true value of that week's net worth. Any subsidiary number could be ascertained by performing a relatively simple calculation. To foretell the prime rate in September, for instance, the subscriber to Witherspoon's newsletter would divide the mystical sum by the current prime rate, subtract the average age of the Politburo, multiply by the number of mice cloned and divide the product by the inflation rate in Argentina. Analogous calculations would divulge a discount rate, the unemployment rate, the Dow Jones average and the amount of the federal deficit.