OPEN DEBATE Rice University's Smalley (left) takes issue with mechanosynthesis and molecular manufacturing as set forth by Foresight Institute's Drexler.
In this C&EN exclusive "Point-Counterpoint," two of nanotechnology's biggest advocates square off on a fundamental question that will dramatically affect the future development of this field. Are "molecular assemblers"--devices capable of positioning atoms and molecules for precisely defined reactions in almost any environment--physically possible?
In his landmark 1986 book, "Engines of Creation: The Coming Era of Nanotechnology," K. Eric Drexler envisioned a world utterly transformed by such assemblers. They would be able to build anything with absolute precision and no pollution. They would confer something approaching immortality. They would enable the colonization of the solar system.
Drexler, who was then a research affiliate with Massachusetts Institute of Technology's Artificial Intelligence Laboratory, also explored in "Engines of Creation" the potentially devastating negative consequences of such a technology. "Replicating assemblers and thinking machines pose basic threats to people and to life on Earth," he wrote in a chapter titled "Engines of Destruction." Because Drexler sees the development of molecular assemblers and nanotechnology as inevitable, he urged society to thoroughly examine the implications of the technology and develop mechanisms to ensure its benevolent application.
Drexler received a Ph.D. in molecular nanotechnology from MIT in 1991. He is the chairman of the board of directors of Foresight Institute, Palo Alto, Calif., which he cofounded, an organization dedicated to helping "prepare society for anticipated advanced technologies."
Richard E. Smalley, University Professor and professor of chemistry, physics, and astronomy at Rice University, Houston, won the 1996 Nobel Prize in Chemistry for the discovery of fullerenes. Much of Smalley's current research focuses on the chemistry, physics, and potential applications of carbon nanotubes. For the past decade, he has been a leading proponent of a coordinated national research effort in nanoscale science and technology.
Like Drexler, Smalley believes the potential of nanotechnology to benefit humanity is almost limitless. But Smalley has a dramatically different conception of nanotechnology from Drexler, one that doesn't include the concept of molecular assemblers. Smalley does not think molecular assemblers as envisioned by Drexler are physically possible. In lectures and in a September 2001 article in Scientific American, Smalley outlined his scientific objections to the idea of molecular assemblers, specifically what he called the "fat fingers problem" and the "sticky fingers problem."
Smalley's objections to molecular assemblers go beyond the scientific. He believes that speculation about the potential dangers of nanotechnology threatens public support for it. Notions about the darker side of nanotechnology have rapidly entered the public consciousness. Two notable examples were an April 2000 essay in Wired magazine titled "Why the Future Doesn't Need Us" by Sun Microsystems cofounder and chief scientist Bill Joy and the 2002 novel "Prey" by Michael Crichton.
This C&EN "Point-Counterpoint" had its genesis in an open letter from Drexler to Smalley posted earlier this year on Foresight Institute's website. That open letter, which challenges Smalley to clarify his "fat fingers" and "sticky fingers" arguments, opens the "Point-Counterpoint." In three subsequent letters, Smalley responds to the open letter, Drexler counters, and Smalley concludes the exchange. C&EN News Editor William G. Schulz coordinated this feature.
MECHANOSYNTHETIC REACTIONS As conceived by Drexler, to deposit carbon, a device moves a vinylidenecarbene along a barrier-free path to insert into the strained alkene, twists 90º to break a pi bond, and then pulls to cleave the remaining sigma bond.