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A Debate About Assemblers


The September 2001 issue of Scientific American devoted six articles and a great deal of text to various perspectives on nanotechnology. The issue included various attacks on the feasibility of molecular assemblers and the work of K. Eric Drexler and his research associates.

Drexler’s textbook Nanosystems was published in 1992. It is still being used as a technical reference all over the world, and to date no significant errors have been found. As the reader can well imagine, if there were any significant errors Scientific American would have pointed them out. They haven’t. The technical claims and conclusions of Nanosystems have withstood almost a decade of serious public review.

Besides Nanosystems, there is now a very large body of technical articles, books, conferences, newsletters, and technical discussion groups that supports the feasibility of molecular machines in general and molecular assemblers in particular.

Two specific articles in the September Scientific American were attempts to cast doubt on the feasibility of nonbiological molecular assemblers.

In “Of Chemistry, Love and Nanobots” Nobelist Richard Smalley stated that: “Self-replicating, mechanical nanobots are simply not possible in our world”. For an in depth analysis of where his technical argument falls short, see the article: “On Physics, Fundamentals, and Nanorobots: A Rebuttal to Smalley’s Assertion that Self-Replicating Mechanical Nanorobots Are Simply Not Possible” at http://www.imm.org/publications/sciamdebate2/smalley/.

George Whitesides, in “The Once and Future Nanomachine,” expresses concerns about many issues that have been previously addressed in the literature. He stated: “Fabrication based on the assembler is not, in my opinion, a workable strategy and thus not a concern.” For commentary and references, see the article: “Many Future Nanomachines: A Rebuttal to Whiteside’s Assertion That Mechanical Molecular Assemblers Are Not Workable and Not A Concern” at http://www.imm.org/publications/sciamdebate2/whitesides/.

While there are quite a few questionable statements in the rest of that issue, nowhere else is there a serious attempt to advance a technical argument against the feasibility of molecular nanotechnology.

How is it possible that an otherwise respectable publication would publish these attacks? None of their technical criticisms of molecular assemblers has withstood scrutiny — all have fallen by the wayside when it became obvious that they were incorrect. Some of the reasons are reviewed in “That’s impossible! How good scientists reach bad conclusions” (see http://www.foresight.org/impact/impossible.html).