From: Eugene.Leitl@lrz.uni-muenchen.de
Date: Sat Nov 25 2000 - 05:59:24 MST
http://www.sciencemag.org/cgi/content/full/290/5496/1526
Is Nanotechnology Dangerous?
Robert F. Service
The only realistic alternative I see is relinquishment: to limit
development of the technologies that are too dangerous, by limiting
our pursuit of certain kinds of knowledge.
Bill Joy, co-founder of Sun Microsystems, in the April issue of Wired.
Bill Joy is nobody's Luddite. As co-founder and chief scientist of Sun
Microsystems in Palo Alto, California, he can match technophile
credentials with anybody on the planet. So when he argued that
research into nanotechnology and other fields should be stopped before
it wipes out humanity, humanity took notice.
To the legion of chemists, physicists, and materials scientists who
spend their lives trying to understand and manipulate matter at the
nanoscale, Joy's warning--published in the April issue of Wired
magazine--felt like a bucket of ice water poured over their
heads. Others had raised similar concerns for decades. But Joy's
status among the digerati lent his allegations new heft. His fears of
nanotechnology, genetic engineering, and robotics research were
broadcast worldwide by news organizations including the Los Angeles
Times and CNN.
Other voices joined the chorus of woe. In June, a group of
nanotechnology aficionados released what they called the Foresight
guidelines. Like Joy, they raised the specter of nanotechnology out of
control. But rather than simply calling for a halt to research, they
outlined measures they said would encourage governmental oversight of
nanotech's development. Such supervision, they argued, could help
prevent accidental catastrophe, much as the National Institutes of
Health's guidelines on recombinant DNA technology helped the emerging
biotech industry avoid accidental releases of genetically modified
organisms.
At first, stunned nanoscience researchers quietly shrugged off the
concerns. But more recently, they've begun to fight back, arguing
vehemently at meetings that what Joy and others fear is at best
implausible and more likely plain wrong. "The research community needs
to divorce itself from the lunatic fringe," says Steven Block, a
biophysicist at Stanford University in Palo Alto.
These fears date back to the 1986 book Engines of Creation, by K. Eric
Drexler. In it, Drexler, a theoretician and chair of a nanotech think
tank called the Foresight Institute, paints a picture of utopia that
will result from the coming age of nanotechnology, a time when
miniature "assemblers" will run atomic-scale assembly lines,
fabricating virtually any imaginable product from the ground up, be it
a car, a carpet, or the steak for your grill. But Drexler also applies
his vivid imagination to nanotechnology's potential downside. Of
particular concern is something he dubs the "grey goo" problem, in
which assemblers replicate themselves ad infinitum, consuming
everything in their path, including plants, pets, and people.
In his Wired article, Joy admits that on the advice of scientist
friends, he initially dismissed Drexler's prophesies of nanoboom and
nanodoom. But last summer, he says, he learned that hypothetical
pieces of futuristic tiny machines were falling into place. One
component of such assemblers--molecule-sized electronic devices--was
"now practical," Joy writes. Further-more, he learned that
self-replication--a feared component of nanomachines running amok--has
already gone beyond biological systems: Researchers had shown that
simple peptide molecules can catalyze their own reproduction. Although
perhaps not around the next bend, self-reproducing nanomachines were
becoming all too plausible, Joy concluded. And that spelled danger.
But all it really spells, Block and others say, is a flawed
extrapolation of current capabilities into the future. "This has all
the depth of a parking lot puddle," says Block. It's simply incorrect
to make the logical leap that, just because simple molecules can
reproduce, scientists and engineers will be able to construct complex
nanomachines that do the same thing. "Nobody has a clue how to build a
nanoassembler, much less get one to reproduce," Block says. Biological
systems, of course, reproduce. But they are both far larger than the
nanoscale and fantastically complex, with separate systems to store
and copy genetic information, produce energy, assemble proteins,
transport nutrients, and so on. Viruses, by contrast, are nanosized,
points out Viola Vogel, a nanoscientist at the University of
Washington, Seattle. But they can reproduce only by co-opting the
machinery of living cells. "Even nature did not make a nanoscale
structure that can self-replicate," she says.
Richard Smalley, a Nobel Prize-winning chemist at Rice University in
Houston, Texas, says that there are several good reasons to believe
that nanomachines of the sort imagined by Drexler and company can
never be made. "To put it bluntly, I think it's impossible," Smalley
says. As he sees it, the idea of little machines that grab atoms and
assemble them into desired arrangements suffers from three
faults. First, he says, it's wrong to think you can just manipulate an
individual atom without handling the ones around it as well. "The
essence of chemistry is missing here. Chemistry is not just sticking
one atom in one place and then going and grabbing another. Chemistry
is the concerted motion of at least 10 atoms." That means to move that
one atom where you want it, you'll need 10 nanosized appendages to
handle it along with all of its neighbors.
Which raises the second problem--what Smalley calls the "fat fingers"
problem. A nanometer is just the width of eight oxygen atoms. So even
if you're trying to build something hundreds of nanometers in size,
"there's just not enough room" in that space to fit those 10 fingers
along with everything they are trying to manipulate. Finally, there's
the "sticky fingers" problem: Even if you could wedge all those little
claspers in there with their atomic cargo, you'd have to get them to
release those atoms on command. "My advice is, don't worry about
self-replicating nanobots," says Smalley. "It's not real now and will
never be in the future."
In an e-mail exchange, Joy replies that he agrees that at the moment
the task of making nanobots seems implausible. "No one denies it's
beyond the state of the art today, but many people see that this isn't
sufficient, in an era of such rapid progress, to allay our concerns."
Twenty or 30 years in the future, he argues, some combination of a
chemical self-assembly process and a bit of directed placement of
other atoms could create synthetic organisms that prey on cells just
as viruses do. And although researchers may raise objections to
specific schemes for making nanobots, "where is the reasoned argument
that says this is impossible?" Joy asks. "Must we have a demonstration
of the danger--a grey goo accident--before we act?"
But this focus on what is possible is beside the point, says Irwin
Feller, who directs the Institute for Policy Research and Evaluation
at Pennsylvania State University, University Park. "All things may be
possible," Feller says. "But society will not place equal value on all
things." Or equal concern, for that matter, if the things are
considered wildly improbable.
Which is not to say there are not reasons to be concerned about
nanotechnology. At a meeting sponsored by the National Science
Foundation in September, representatives from the research community,
think tanks, and government funding agencies huddled to discuss
emerging concerns for the field. Rather than nanobots, the greatest
issues were social: Is the educational system up to the task of
training enough nanotech workers? Could nanoscience's progress in
areas such as electronics undermine traditional businesses on which
thousands of jobs depend? Could the decreasing cost of tools for doing
nanoscience and molecular biology make it easier for terrorists or
other small groups to engineer dangerous microbes? Such concerns, the
researchers concluded, are very real indeed.
But that wasn't all. The biggest problem nanotechnology could face
down the road is public acceptance, said Richard Klausner, head of the
National Cancer Institute. Klausner wasn't worried about
nanobots. Rather, he argued that nanoscience is exploring numerous
revolutionary medical applications, such as creating implantable
sensors to watch for the signature molecules of cancer. But unless
patients are aware of the development of such tools beforehand, many
of them may balk at having their bodies invaded by technology.
To better understand such concerns ahead of time, researchers need to
involve outsiders in the development process, much as AIDS activists
helped set priorities for research on AIDS drugs, says Klausner. "I
think that didn't happen very effectively over the last 10 years with
genetically modified organisms," he adds. And that's a danger that
nanotechnology developers would like to avoid.
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