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Drexler-Smalley debate gets nowhere

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  • Mark Gubrud
    The December issue of Chemical and Engineering News features an further exchange between K. Eric Drexler and Richard Smalley on the feasibility of assembler
    Message 1 of 1 , Dec 1, 2003
      The December issue of Chemical and Engineering News features an further
      exchange between K. Eric Drexler and Richard Smalley on the feasibility
      of assembler technology. The full text can be found at

      This elaboration of the Drexler-Smalley debate represents a further
      delineation of the issues involved, but makes little progress toward any
      resolution. Smalley tosses around words like "pretend" and "assume" and
      himself assumes a pedantic stance, as if Drexler were a particularly
      obtuse student. Drexler prattles about the capabilities of his
      hypothetical nanofactories, asserting they "will be powerful enablers"
      and that "failure to develop molecular manufacturing would be equivalent
      to unilateral disarmament." Although he restates the basics of his
      theory, Drexler fails to decisively rebut Smalley's claim that the "list
      of conditions and synthetic targets that will actually work reliably
      with mechanosynthesis can [not] be anything but a very, very short

      Smalley's basic argument is that "You need to guide the reactants down a
      particular reaction coordinate, and this coordinate treads through a
      many-dimensional hyperspace", and that this can only be ensured by
      something like an enzyme, which is "a fairly large group of other atoms
      arranged in a complex, articulated, three-dimensional way to activate
      the substrate and bring in the reactant, and massage the two until they
      react in just the desired way." Drexler counters that nanofactories
      would make use of special enzymelike tool molecules in order to achieve
      just what Smalley is talking about, but we should note also that at
      least some mechanosynthetic reactions can be arranged much more simply.
      Whether the loop of self-replication in "machine-phase" systems can in
      fact be closed remains undecided by these arguments.

      Smalley's argument is still little more than a considered judgement.
      Drexler can hardly be expected to solve all problems involved in
      assembler design, let alone demonstrate a working assembler, in order to
      prove his theory. But he should make a better effort to engage the
      argument directly.

      Smalley is clearly off-target in some of his statements, such as the
      claim that enzymes only work in water. Natural proteins are evolved to
      work in water; this does not mean that other enzymelike molecular tools
      would not work in vacuum; in fact some protein enzymes work just fine
      out of solution. But this is a side issue.

      The real issue is one that can only be resolved by much more research
      directed toward studying mechanosynthesis and assessing the problems
      involved in assembler and nanofactory design. Here is where it seems to
      me that Smalley is clearly in the wrong. He and other senior-level
      people in the NNI have worked to exclude such research from funding. It
      is becoming perfectly transparent that the reason is an effort to stifle
      controversy about the serious social implications of advanced,
      assembler-based nanotechnology. This is bad enough that if, in the
      future, it is determined that assembler-based nanotechnology is
      feasible, the current funding regime will be looked back on as a science
      policy scandal. We cannot rely on Smalley's intuition to decide this
      issue any more than we can rely on Drexler's.

      Mark Avrum Gubrud
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