K. Eric Drexler - Controversy

Controversy

See also: Drexler–Smalley debate on molecular nanotechnology

Drexler's work on nanotechnology was criticized as naive by Nobel Prize winner Richard Smalley in a 2001 Scientific American article. Smalley first argued that "fat fingers" made MNT impossible. He later argued that nanomachines would have to resemble chemical enzymes more than Drexler's assemblers and could only work in water. Drexler maintained that both were straw man arguments, and in the case of enzymes, wrote that "Prof. Klibanov wrote in 1994, '... using an enzyme in organic solvents eliminates several obstacles ...'" Drexler had difficulty in getting Smalley to respond, but in December 2003, Chemical and Engineering news carried a 4 part debate. Ray Kurzweil spends four pages in his book 'The Singularity Is Near' to showing that Richard Smalley's arguments are not valid, and disputing them point by point. Kurzweil ends by stating that Drexler's visions are practicable and even happening already.

One of the barriers to achieving molecular nanotechnology is the lack of an efficient way to create machines on a molecular/atomic scale. One of Drexler's early ideas was an "assembler", a nanomachine that would comprise an arm and a computer that could be programmed to build more nanomachines. If an assembler could be built, it might then build a copy of itself, and thus potentially be useful for efficient mass production of nanomachines. But the lack of a way to first build an assembler remains the sine qua non obstacle to achieving this vision.

A second difficulty in reaching molecular nanotechnology is design. Hand design of a gear or bearing at the level of atoms is a grueling task. While Drexler, Ralph Merkle, and others have created a few designs of simple parts, no comprehensive design effort for anything approaching the complexity of a Model T Ford has been attempted.

A third difficulty in achieving molecular technology is separating successful trials from failures, and elucidating the failure mechanisms of the failures. Unlike Darwinian evolution, which proceeds by random variations in ensembles of organisms combined with deterministic reproduction/extinction as a selection process to achieve great complexity after billions of years (a set of mechanisms that Richard Dawkins has referred to as a "blind watchmaker"), deliberate design and building of nanoscale mechanisms requires a means other than reproduction/extinction to winnow successes from failures. Such means are difficult to provide (and presently non-existent) for anything other than small assemblages of atoms viewable by an AFM or STM.

Thus, even in the latest report "A Matter of Size: Triennial Review of the National Nanotechnology Initiative" put out by the National Academies Press in December 2006, (roughly twenty years after Engines of Creation was published) no clear way forward toward molecular nanotechnology is seen, as per the conclusion on page 108 of that report:

Although theoretical calculations can be made today, the eventually attainable range of chemical reaction cycles, error rates, speed of operation, and thermodynamic efficiencies of such bottom-up manufacturing systems cannot be reliably predicted at this time. Thus, the eventually attainable perfection and complexity of manufactured products, while they can be calculated in theory, cannot be predicted with confidence. Finally, the optimum research paths that might lead to systems which greatly exceed the thermodynamic efficiencies and other capabilities of biological systems cannot be reliably predicted at this time. Research funding that is based on the ability of investigators to produce experimental demonstrations that link to abstract models and guide long-term vision is most appropriate to achieve this goal.