MAN VS. MACHINE CHESS MATCH RAISES QUESTIONS OF INTELLIGENCE.

Byline: George Johnson The New York Times

Whether the machine or the man ultimately wins the rematch between Deep Blue and Garry Kasparov, it is probably just a matter of time before a computer prevails. What is far less certain is just what to make of such a victory.

How to define intelligence and decide who or what has it remains among science's unsolved, and possibly unsolvable, problems. Whether a machine like Deep Blue, combining lightning-fast search power with a growing database of chess knowledge, can be said to think depends on one's philosophical prejudices. And it can be surprising to learn who holds which view.

It would seem likely that Deep Blue's inventors would be touting their brainchild as a landmark in artificial intelligence, and that Kasparov would be dismissing Deep Blue as a mere automaton, triumphing when it does mostly because of an inhuman ability to consider 200 million chess positions in the time it takes to furrow an eyebrow.

Its ability to do that has enabled it to hold its own against Kasparov, and after four games they are deadlocked. Each has won once and two games were drawn. The last two games were scheduled for Saturday and today.

During all this, IBM scientists have taken pains to emphasize that Deep Blue is just a glorified calculator. On a special Web page put up for the occasion, IBM describes its chess expert like this: ``Deep Blue is a machine that is incapable of feeling or intuition. . . . Deep Blue is stunningly effective at solving chess problems, but it is less `intelligent' than even the stupidest human.''

Kasparov has been paying Deep Blue the compliment of describing it as though it were intelligent. After beating the computer last year, he said it exhibited the stirrings of genuine thought. ``I believe signs of intelligence can be found in the net result, not in the way the result is achieved,'' he said before this week's rematch. ``I don't care how the machine gets there. It feels like thinking.''

Kasparov is taking what philosophers call the functionalist position. Intelligence is as intelligence does. From his point of view, the digital calculations taking place in Deep Blue's processors are as invisible as the firings of neurons in a human opponent. Biological or mechanical, the brain is a black box. All that matters is the outcome.

The IBM team, which knows the workings of the computer too well to be so impressed, is coming down on the side of those who argue that intelligence requires an ability to learn from mistakes, a talent still lacking in Deep Blue; and perhaps even emotions and the chimerical quality called consciousness.

Maybe when scientists learn more about human brains, they will be just as unimpressed by how Kasparov thinks through a game. If a brain is just a biological computer, as most neuroscientists assume, mysterious qualities like intuition should turn out to be a matter of calculation, searching a neurological database of possible solutions. Brains make up for their slowness by learning to recognize the most promising possibilities. Computers make up for their ignorance and poor skills at pattern recognition by exhaustively considering possibilities that a human wouldn't bother with.

But without programmed lessons in chess strategy, even a machine as powerful as Deep Blue would quickly become lost in the Borgesian labyrinth of possible chess games, searching and searching and never finding the right move.

The problem is what computer scientists call combinatorial explosion, and it happens even in a game like tick-tack-toe. The first player puts a mark in one of nine different cells. For each of those plays, the opponent has a choice of eight different countermoves. Then for each of those eight possibilities, the first player can respond with seven different plays. Altogether there are 9x8x7x6x5x4x3x2x1, or 362,880, ways to fill in the crisscross lines with X's and O's. A computer that held this sprawling map of potentialities in its silicon brain would have the game down cold.

For chess, that kind of omniscience is impossible.