It wasn't quite Dan Aykroyd and Jane Curtin tossing insults at each other while ostensibly debating a serious political issue. But an exchange between a Nobel laureate and a nanotechnology visionary last week was reminiscent of that old ''Saturday Night Live'' sketch.
The magazine Chemical & Engineering News, which published the exchange in its Dec. 1 issue, even labeled it ''Point/Counterpoint,'' just like the ''60 Minutes'' debates that Mr. Aykroyd and Ms. Curtin lampooned.
This time, though, the subject of debate was whether it is possible to build a nanobot -- a robot the size of a bacterium or a virus or even smaller.
Dr. K. Eric Drexler, chairman of the Foresight Institute, which promotes this vision, took the pro-nanobot view. Dr. Drexler, indeed, invented the word ''nanotechnology'' a couple of decades ago. The word comes from nanometer, a billionth of a meter, which is a convenient unit for expressing the sizes of atoms and molecules.
In ''Engines of Creation'' (1986), Dr. Drexler proposed his idea of ''molecular assemblers,'' nanobots that would be able to build almost anything, including copies of themselves. Swarms of nanobots may one day be able to perform tasks like breaking down pollutants into harmless molecules or repairing damage in individual cells, perhaps even reversing the effects of aging.
