Today Jeopardy , Tomorrow the World

Do you think that 50,000 years ago, as Cro-Magnons first began to filter into Europe, the resident Neanderthals scratched their bulky brows and wondered "gee, could these guys replace us?"

I strongly suspect that today, Homo sapiens is about to be replaced. But these next-gen sentients won't wander in from Africa, as the gracile Cro-Magnons did: They'll roll through the doors of artificial intelligence labs.

We're inventing our successors. And as a modest sideshow in this dramatic development, an IBM computer with the come-hither moniker "Watson" will be crossing swords with two accomplished humans this week on the popular television quiz program, Jeopardy.

Depending on your personal philosophies -- or maybe your susceptibility to the last blog post to cross your screen -- you're either betting on the vast, perfectly reliable memory banks and microsecond reaction times of Watson, or on the supple synapses of its human opponents, Ken Jennings and Brad Rutter. Most people, I assume, will bet on their own species.

But the big picture is this: It doesn't matter who wins the Jeopardy cash. This is a skirmish -- a Bull Run battle that won't change the outcome of the war. The machines are getting better, and despite the opinion you have of your kids, we're not.

In 1830, in a demonstration for the fledgling B&O Railroad, a small locomotive named Tom Thumb inadvertently got into a race with a horse -- and lost. This has become a famous story only because it was the last time that horses had a chance. Jeopardy may not be the last time that humans can hope to outwit machines, but that day will come, and it will probably come within this century.

Now a few points to note: This is not the first time that IBM computers have taken on protoplasmic adversaries. In 1996 and 1997, IBM machines played chess against Gary Kasparov, losing the first time, but winning (barely) the second. Of course, chess is an activity whose rigid rules allow mindless computation to eventually overwhelm skill and strategy.

Winning at Jeopardy requires more than computation, and indeed, it demands more than simply a phalanx of spun-up hard drives, loaded with facts. If the contest were merely a matter of information look-up, the odds on Watson would be short indeed. The real challenge for the computer will not be knowing the answer, but understanding the question.

Humans can unravel syntax and context far better than machines, at least so far. But it takes years to develop that skill in children, and computers are often asked to do so right out of the box. That's why many of the most interesting experiments in artificial intelligence involve devices that can interact and learn. Machines that can self-improve.

But games aside, some people -- actually, quite a few -- figure that no synthetic sentient will ever be able to do things humans take for granted, such as performing stand-up comedy, writing meaningful poetry, or simply knowing when it's safe to jaywalk. These skeptics are perfectly willing to admit that we might engineer a synthetic heart or kidney, but the three pound organ sitting between their ears -- well, that's sacred, man. Nothing could replicate its functionality, they aver.

All right, but consider the following. The processing power of computers is currently doubling every two years. Within a half-generation, the raw reckoning ability of your laptop will lap yours. In addition, human thought happens at the speed of neurons, with the signals ambling along at hundreds of feet per second, at most. Computer signals move at the speed of light, more than a million times faster.

The physicist Philip Morrison once described our brains as "slow-speed computers, operating in salt water." Harsh, but accurate.

In addition, your gray matter is boxed in by a brain case whose size is dictated by the sustainable body plan of a hominid. It weighs three pounds and operates at the same power level as a fridge light. A thinking machine, of course, needn't be hemmed in or energy starved.

Still and all, there's no denying the obvious: Neither Watson nor its chess-playing predecessors really think. Despite decades of work in artificial intelligence, no machine can unembarrassedly make that claim. But as the AI researchers say, don't confuse lack of success with lack of progress.

In a recent article in the Atlantic, Brian Christian describes how he recently took part in an annual contest between humans and computers (based on the well-known Turing test), and came out on top. In the battle between carbon and silicon sentience, he believes Homo sapiens will always be able to outfox the machines.

I'd like to think he's right, but somewhere deep in my soft, squishy cerebral cortex, I know he's whistling in the dark.