facing a scientific theory they disagree with, scientists
are supposed to try to disprove it by scientific methods.
Molecular manufacturing includes a substantial, well-grounded,
carefully argued, conservative body of work. So why
do scientists treat it as though it were pseudoscience,
deserving only political attack? And how should they
be approaching it instead? To answer this, we have
to consider the gap between science and engineering.
do experiments and develop theories about how the
world works. Engineers apply the most reliable of
those theories to get predictable results. Scientists
cannot make reliable pronouncements about the complex
"real world" unless their theory has been
field-tested by engineering. But once a theory is
solid enough to use in engineering, science has very
little of interest to say about it. In fact, the two
practices are so different that it's not obvious how
they can communicate at all. How can ideas cross the
gap from untested theory to trustworthy formula?
Appendix A of Nanosystems*, Eric Drexler describes
an activity he calls "theoretical applied science"
or "exploratory engineering". This is the
bridge between science and engineering. In theoretical
applied science, one takes the best available results
of science, applies them to real-world problems, and
makes plans that should hopefully work as desired.
If done with enough care, these plans may inspire
engineers (who must of course be cautious and conservative)
to try them for the first time.
bulk of Appendix A discusses ways that theoretical
applied science can be practiced so as to give useful
and reliable results, despite the inability to confirm
its results by experiment:
For example, all classes of device that would violate
the second law of thermodynamics can immediately be
rejected. A more stringent rule, adopted in the present
work, rejects propositions if they are inadequately
substantiated, for example, rejecting all devices
that would require materials stronger than those known
or described by accepted physical models. By adopting
these rules for falsification and rejection, work
in theoretical applied science can be grounded in
our best scientific understanding of the physical
presents theoretical applied science as a way of studying
things we can't build yet. In the last section, he
ascribes to it a very limited aim: "to describe
lower bounds to the performance achievable with physically
possible classes of devices." And a limited role:
"In an ideal world, theoretical applied science
would consume only a tiny fraction of the effort devoted
to pure theoretical science, to experimentation, or
to engineering." But here I think he's being
too modest. Theoretical applied science is really
the only rigorous way for the products of science
to escape back to the real world by inspiring and
might draw a useful analogy: exploratory engineers
are to scientists as editors are to writers. Scientists
and writers are creative. Whatever they produce is
interesting, even when it's wrong. They live in their
own world, which touches the real world exactly where
and when they choose. And then along come the editors
and the exploratory engineers.
"This doesn't work. You need to rephrase that.
This part isn't useful.
And wouldn't it be better to explain it this way?"
Exploratory engineering is very likely to annoy and
the extent that exploratory engineering is rigorously
grounded in science, scientists can evaluate it --
but only in the sense of checking its calculations.
An editor should check her work with the author. But
she should not ask the author whether he thinks she
has improved it; she should judge how well she did
her job by the reader's response, not the writer's.
Likewise, if scientists cannot show that an exploratory
engineer has misinterpreted (misapplied) their work
or added something that science cannot support, then
the scientists should sit back and let the applied
engineers decide whether the theoretical engineering
work is useful.
manufacturing researchers practice exploratory engineering:
they design and analyze things that can't be built
yet. These researchers have spent the last two decades
asking scientists to either criticize or accept their
work. This was half an error: scientists can show
a mistake in an engineering calculation, but the boundaries
of scientific practice do not allow scientists to
accept applied but unverified results. To the extent
that the results of theoretical applied science are
correct and useful, they are meant for engineers,
not for scientists.
is often accused of declaring that nanorobots will
work without ever having built one. In science, one
shouldn't talk about things not yet demonstrated.
And engineers shouldn't expect support from the scientific
community -- or even from the engineering community,
until a design is proved. But Drexler is doing neither
engineering nor science, but something in between;
he's in the valuable but thankless position of the
cultural ambassador, applying scientific findings
to generate results that may someday be useful for
as great a scientist as Lord Kelvin can be wrong about
something as mundane and technical as heavier-than-air
flight, then lesser scientists ought to be very cautious
about declaring any technical proposal unworkable
or worthless. But scientists are used to being right.
Many scientists have come to think that they embody
the scientific process, and that they personally have
the ability to sort fact from fiction. But this is
just as wrong as a single voter thinking he represents
the country's population. Science weeds out falsehood
by a slow and emergent process. An isolated scientist
can no more practice science than a lone voter can
proper role of scientists with respect to molecular
manufacturing is to check the work for specific errors.
If no specific errors can be found, they should sit
back and let the engineers try to use the ideas.
A scientist who declares that molecular manufacturing
can't work without identifying a specific error is
being unscientific. But all the arguments we've heard
from scientists against molecular manufacturing are
either opinions (guesses) or vague and unsupported