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
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