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While this definition would be quite reasonable in an article on high resolution lithography, its use in an article which is centered on molecular manufacturing as discussed both in Nanosystems and at the Fourth Foresight Conference on Molecular Nanotechnology is not only inappropriate but extremely misleading."Nanotechnology is the manufacture of materials and structures with dimensions that measure up to 100 nanometers (billionths of a meter)."
In response, Reifman said "...I was quite upset to be quoted entirely out of context regarding Eric Drexler being 'the messiah'. That comment was mentioned in jest when I talked briefly with the writer...""'That's the messiah,' confides Edward M. Reifman, D.D.S. The Encino, Calif., dentist has paid hundreds of dollars to attend a conference to hear about robotic machines with working parts as small as protein molecules. Reifman nods toward K. Eric Drexler, the avatar of nanotechnology."
The use of biased words such as "strange" or "acolytes" is pervasive. It's an easy way to put a negative spin on a story in the absence of anything technically substantive. Some biased usages are noted in the following text, but their sheer number makes it awkward to comment on all of them."Drexler has just finished explaining to a strange mix of scientists, entrepreneurs and his own acolytes that nanotech may arrive in one to three decades. The world, in his view, has not fully grasped the implications of molecular machines that will radically transform the way material goods are produced."
This is a more subtle bit of misdirection. There are now a myriad different definitions of the word "nanotechnology." While this definition would be quite unobjectionable in a story on (say) ultra high resolution lithographic methods, in the present story -- which is focused almost exclusively on molecular manufacturing -- its use is inappropriate and leads to confusion. For purposes both of the story and of this review, an appropriate definition of "nanotechnology" is: a manufacturing technology able to inexpensively fabricate most structures consistent with natural law, and to do so with molecular precision. This is radically different from "structures with dimensions that measure up to 100 nanometers.""Nanotechnology is the manufacture of materials and structures with dimensions that measure up to 100 nanometers (billionths of a meter)."
Properly speaking, none of the items mentioned is nanotechnology. The synthetic methods used in chemistry today can economically make many structures, but certainly cannot make (for example) molecular computers or low-cost shatterproof diamond sculpted with molecular precision. Scanning probe methods are even more limited in the range of structures they can currently make. However, further developments in both chemistry and proximal probe methods could be important or crucial in the development of nanotechnology. Some of the research in these areas can reasonably be described as "leading to nanotechnology.""Its definition applies to a range of disciplines, from conventional synthetic chemistry to techniques that manipulate individual atoms with tiny probe elements. In the vision promulgated by Drexler, current nano-scale fabrication methods could eventually evolve into techniques for making molecular robots or shrunken versions of 19th century mills."
While manufacturing costs will be low, other factors will likely increase the purchase price of "finished goods." As an example: the manufacturing cost of software is low, but the purchase price varies over a wide range."In the course of a few hours, manufacturing systems based on Drexler's nanotechnology could produce anything from a rocket ship to minute disease-fighting submarines that roam the bloodstream. And, like biological cells, the robots that populate a nanofactory could even make copies of themselves. Finished goods in this new era could be had for little more than the cost of their design and of a raw material - such as air, beet sugar or an inexpensive hydrocarbon feedstock.
Eric Drexler testified at the senate hearings on "New Technologies for a Sustainable World" held by Al Gore shortly before Gore became a candidate for Vice President. The transcript of the statements by both Drexler and Gore is available on the web, as is Drexler's prepared statement.The Drexlerian future posits fundamental social changes: nanotechnology could alleviate world hunger, clean the environment, cure cancer, guarantee biblical life spans or concoct superweapons of untold horror."
The National Space Society might object to the claim that the allure of space development and settlement has faded. Note also that we are going to "transcend the limits imposed by economics and mortality." This is a hyperbolic exaggeration by the writer. The ability to manufacture products at a lower cost does not "transcend the limits imposed by economics"; nor do improvements in medical technology -- even the rather remarkable improvements that nanotechnology is likely to make feasible -- render us immortal. Today we live in a world of greater material abundance than in centuries past, and we live longer and healthier lives. In the future this trend is likely to continue and nanotechnology is likely to play a major role."Scientific visionaries have turned their attention from outer to inner space, as the allure has faded from dreams of colonizing another planet and traveling to other galaxies. Computer mavens and molecular biologists have replaced rocket scientists as the heroes that will help transcend the limits imposed by economics and mortality. 'Whether or not Drexler's utopian ideas are correct, they come at a time when a variety of fields have reached stasis,' says Seth Lloyd, a professor and specialist in quantum computation at the Massachusetts Institute of Technology. 'You don't come across many fields that have as bold a project as the space program was.'"
Referring to Admiral David Jeremiah, USN (Ret.), former Vice Chairman of the Joint Chiefs of Staff for Generals Powell and Shalikashvili as "...a retired navy admiral..." is somewhat like referring to Colin Powell as "... a retired general." Jeremiah was more than an attendee: his presentation on Nanotechnology and Global Security was extremely impressive."Submicroscopic machines that can save or destroy the world appeal to anyone from a retired navy admiral to a technophile dentist to eager students - all of whom attended the nanotechnology conference. Reifman, the dentist, is a disciple who carries the message of nanotechnology to patients waiting nervously in his dental chair. He tells them of robots as small as a microbe that will painlessly refurbish a tooth or build a new one from scratch. 'You'll be able to be a chocoholic without guilt,' he predicts."
Drexler's first published paper on nanotechnology, which appeared in the Proceedings of the National Academy of Sciences USA in 1981, is now available on the web."Drexler has purveyed his nanovisions for almost two decades. In recent years, however, his intricately constructed pictures of the next century and beyond have begun to be overtaken by real investigations into nanotechnology. What inspires actual researchers at the nanoscale is infinitely more mundane than molecular robots - but also more pragmatic. Nanotechnology, in this guise, may not contain the ready promise of virtually limitless global abundance and human mastery of the material world. But it may move beyond mere speculation to produce more powerful computers, to design new drugs or simply to take more precise measurements."
The "host of physical forces" is too vague to comment on -- later in this review we'll see some more specific "problems." We'll also defer comments on the unspecified "critics" until some specific examples are presented."Researchers can now manipulate atoms or molecules with microscopic probe elements, marshal the 20 basic amino acids to form new proteins not found in nature, or help organic molecules spontaneously assemble themselves into ordered patterns on a metal surface. This work certainly presents the prospect of providing new tools for the engineering community. Ironically, it also demonstrates the difficulties of using individual atoms or molecules as building blocks, given the presence of a host of physical forces that may displace them. In fact, some of Drexler's sharpest critics are engineers and scientists who spend their time toiling in the nanorealm."
Yet another example of biased terminology. Drexler's scenarios are "fanciful." The terms "infeasible" and "contrary to physical law" have well defined meanings. As the question of interest is the feasibility of nanotechnology, the more hard edged statements that the proposals are feasible or infeasible should be used. This would, of course, force a more rigorous (and useful) discussion of the issues. "Fanciful" is a term which means nothing, other than the writer can't find any substantive grounds for criticism."Drexler's fanciful scenarios, nonetheless, have come to represent nanotechnology for many aesthetes of science and technology. The phenomenon is not uncommon in the sociology of science. The public image of a certain field or concept, shaped by futurists, journalists, and science-fiction scribes, contrasts with the reality of the often plodding and erratic path that investigators follow in the trenches of day-to-day laboratory research and experimentation."
"Mr. Peabody"????Drexler, the 40-year-old guru of the nanoists, speaks with an exaggerated professorial tone that is faintly reminiscent of the pedantic 1960s cartoon character Mr. Peabody. Over a buffet lunch in early November at the biennial conference sponsored by his Foresight Institute - an organization he set up in Palo Alto, Calif., to help pave the way for nanotechnology - Drexler pours milk into his ice tea. He explains that the milk binds the tannins that may lead to throat cancer."
Scientific American has just published a story based largely on ad hominem attacks on Drexler, using systematically biased language, which constantly denigrates a technological objective that is widely thought to be feasible. This would appear to provide some evidence in support of Drexler's statement. We'll have more to say on planning horizons later."During the meal, he complains about the shortsightedness of the scientific and technological research establishment in the U.S., which has largely ignored his brand of nanotechnology. Drexler is familiar with dreams that don't come true. In the 1970s he volunteered to work with space colonization advocate Gerard K. O'Neill to plan various scenarios for extraterrestrial living; he even wrote a paper on mining asteroids in his freshman year at M.I.T. Drexler and other nanoists view their technology as a means to rejuvenate a moribund space program that has no immediate plans to create retirement communities on Mars. Nanotechnology would allow the manufacture of strong, light materials that would go into space transport vehicles."
It's quite entertaining to watch the mental gymnastics of those who think nanotechnology is infeasible but who simultaneously respect Feynman, who said: "The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big.""The basic ideas behind small, self-replicating machines did not originate with Drexler. The renowned mathematician John Von Neumann, a father of the field of artificial life, ruminated about a machine that could make copies of itself. And in a much cited 1959 speech, Nobelist Richard P. Feynman talked about the ability to build things by placing each atom in a desired place. The self-assured Feynman used to toy playfully with the notion of making things small, musing on the theme with the humor of a Brooklyn-accented, Borscht Belt comic. Feynman even proposed a competition between high schools: "The Los Angeles high school could send a pin to the Venice high school on which it says [on the pinhead], 'How's this?' They get the pin back, and in the dot of the 'i' it says, 'Not so hot.'" Drexler, unlike the puckish Feynman, approaches his passion with a dour earnestness. The message: Nanotechnology is coming, we must prepare now."
Damning with faint praise. Also note that "...Drexler set down a detailed description...." The implication here is that "a detailed" prediction of the future is impossible, Drexler made a detailed prediction, therefore Drexler is attempting to do the impossible. Both Engines and Unbounding the Future present several plausible scenarios. Note that considering multiple plausible scenarios about what might happen in the future is very different from giving a single detailed description about what will happen. Scenario planning is an established method of guiding decision making in the face of an uncertain future, and Drexler quite explicitly adopted this methodology. Given that nanotechnology is feasible -- a technical question that Scientific American seems intent on avoiding -- then scenario planning is a useful tool for gaining some insight into the range of issues that might arise and some of the possible options."Drexler, though, can rightly claim credit for bringing wide exposure to an enticing idea. In his 1986 work Engines of Creation, Drexler, like Jules Verne and H.G. Wells, succeeded in depicting a world altered forever by the advent of a new technology. In Engines, Drexler introduced the concept of an "assembler," a robotic device with dimensions of a tenth of a micron (a millionth of a meter) or less, that can pick up and position a reactive molecule so that it interacts with another molecule, as though it were a Lego block snapping into place. He has also described mills equipped with belts and rollers to process molecules. A battery of nanocomputers - perhaps collections of molecular rods that change position to represent distinct logic states - could broadcast instructions to trillions of assemblers at once. The computers could also instruct assemblers to self-replicate. In his book, Drexler set down a detailed description of how society would be transformed by nanotechnology. Engines presents a picture of a Manichaean balance of utopian/dystopian scenarios."
An unbiased paragraph describing some things that nanotechnology should make feasible.Combining nanocomputers with molecular machines would allow almost anything that can be designed to be made from a variety of inexpensive raw materials, perhaps even dirt, sunlight and air. Assemblers could string together atoms and molecules so that most goods could be made from diamond or another hard material, giving the most ordinary objects a remarkable combination of strength and lightness."
The potential payoff from the development of nanotechnology is indeed quite large."The cost per kilogram of goods produced by nanomanufacturing would equal the price of potatoes. The resulting nanoworld, in which everyone is wealthy because of the drastic reduction in the cost of goods, would flummox economists, those scientists of scarcity. A jumbo airliner could be purchased for the current price of an automobile. A homeowner would pour acetone into a household manufacturing system, similar in appearance to a microwave oven. An hour later, out would come a computer, a television set or a compact-disc player. A home food-growing machine could rapidly culture cells from a cow to create a steak, a godsend to the animal-rights movement."
There is experimental work today involving the interpretation of electroencephalograms to control equipment. There is also work aimed at alleviating certain handicaps by connecting an electronic control system to the nerves controlling a muscle if the person's own nervous system is unable to stimulate those nerves; and work aimed at directly stimulating the auditory nerves of a deaf person. Future extensions of this type of research can be envisioned. Engines, in a section explicitly aimed at disentangling what is likely to be feasible from what is not, discusses the feasibility of directly connecting transducers to nerves, making possible what might be viewed as a limited type of "telepathy." (In some sense, ordinary speech is a type of "telepathy," as it permits the thoughts in one mind to be transferred to another mind)."Minuscule submarinelike robots made by assemblers would extend life or reverse aging by killing microbes, by undoing tissue damage from heart disease or by reversing DNA mutations that cause cancer; the nanomachines would help revive bodies preserved in cryogenic storage by repairing frostbite damage to the brain and other organs. (Drexler, in fact, plans to sign up to have his body frozen after death.) Engines of Creation even speculates about nanotechnology providing the basis for telepathy or for radically changing one's body."
"Military applications of molecular manufacturing have even greater potential than nuclear weapons to radically change the balance of power." --- Admiral David E. Jeremiah, USN (Ret), former Vice Chairman of the Joint Chiefs of Staff."On the dark side, assemblers would streamline the production of superweapons, allowing rapid fabrication of a tank or a surface-to-air missile. And then there is the "gray goo" problem - the possibility that nanodevices might be designed to replicate uncontrollably, like malignant tumor cells, and reduce everything to dust within days."
We're now back to Drexler this, Drexler that, and biased adjectives. Drexler makes a "plea," has "ruminations," etc. etc. etc. The basic technical issues are once again pushed aside to focus on the irrelevant."Ruminations in Engines of Creation about gray goo and extended life spans provoked guffaws from many scientists. In 1992 Drexler responded to the criticism with Nanosystems, which attempts to give his tiny machines a grounding in the underlying essentials of physics, chemistry and biology. Nanosystems heavy technical emphasis was a plea from Drexler for respectability. The subtext: I am not a flake. But the book remains largely an object of curiosity to the scientific community. It has been hard for many scientists, engineers and technicians to take seriously a section at the end that shows components of assemblers similar to large-scale mechanical devices. For example, a six-legged platform imitates the ones used to tilt flight simulators into different attitudes of yaw, pitch and roll. Its size: only 100 nanometers across, no bigger than a virus. "This is not science - it's show business," says Julius Rebek, a leading researcher in the chemistry of self-assembly at M.I.T."
The denigration of positional control (which sometimes appears in the
self-assembly research community) is unjustified. We note that positional
control is used extensively at the macroscopic scale. Indeed, Homo sapiens
is viewed as the tool using species -- without the ability to hold tools
and apply them in a positionally controlled fashion to workpieces ranging
from flint knives to computer keyboards we would no doubt still be shivering
in a cave. Recent experimental work has indeed demonstrated that positional
control can be applied at the molecular level, and theoretical work has
long supported exactly the same conclusion. Recent
theoretical work on the use of a positionally controlled ethynyl radical
to selectively abstract chosen hydrogen atoms from the diamond (111) surface
provides the most recent and specific support for the idea that positionally
controlled molecular tools can provide a mechanism for synthesizing specific
complex diamondoid structures. There is growing interest in nanotechnology from the mainstream, though the significance of "alienation" from the mainstream is debatable. When I submitted the first paper describing a public key system in 1975, it was rejected by the referee with the note that "I am sorry to have to inform you that the paper is not in the main stream of cryptography thinking...." That was, of course, the point of the paper. Public key cryptography introduced a new paradigm -- a point that the referee was too dull to grasp."Despite his alienation from mainstream science and engineering, Drexler continues to amass devotees, particularly among computer scientists enticed by the prospect of making tangible anything they can specify with a set of three-dimensional coordinates. "Nanotechnology will reduce any manufacturing problem, from constructing a vaccine that cures the common cold to fabricating a starship from the elements contained in sea water, to what is essentially a software problem," writes physicist and science-fiction author John G. Cramer."
Silicon Valley does indeed have a relatively high proportion of highly trained, technically competent people who are used to making their own judgements about new technologies."Silicon Valley, that mecca for aficionados of things small, hosts a disproportionate number of nanoists. Apple Computer has helped sponsor the Foresight Institute's conferences - the most recent one last November drew more than 300 people, double the attendance of the 1993 gathering. A researcher at the Xerox Palo Alto Research Center, Ralph C. Merkle, who made a name for himself in computer cryptography, spends his time creating models of molecular machine components. (Merkle has already signed up to have his head frozen.)"
Drexler has not sought grants from government sources but has instead sought to fund research and education through nonprofit public foundations. He has done a remarkable amount on a shoestring budget -- I encourage donations to the Institute for Molecular Manufacturing and the Foresight Institute."In 1991 John Walker, the reclusive founder of Autodesk, a California software company, donated $175,000 to help start the Institute for Molecular Manufacturing, a research organization. Most of the institute's grant money has gone to pay Drexler to work on projects such as computer simulations of molecular gears, bearings and other parts."
Students are indeed taking a strong interest in nanotechnology:"The Drexler following includes speculative thinkers such as artificial-intelligence pioneer Marvin L. Minsky. Nanotechnology also seems to inspire government laboratories seeking to remake their image. Oak Ridge National Laboratory has let one of its modeling groups devote extensive effort to simulations of molecular bearings and shafts. Administrator Daniel S. Goldin of the National Aeronautics and Space Administration sees nanotechnology as a means of building smaller and lighter space vehicles. And the NASA Ames Research Center has scheduled a workshop for this spring to examine how its supercomputers might be used to provide models of nanodevices. Perhaps the most noteworthy trend - or the most disturbing one, to critics of the nanoist vision - is the appeal that the technology holds for students."
Computational chemists generally seem able to absorb the idea of nanotechnology quite easily. One reason for this is that they have the training and the tools to evaluate proposals for molecular machines. Give them a PDB file and tell them that it describes a molecular structure that's supposed to do something useful, and they'll happily model it. Sometimes they come back and tell you that it works and it's a great design. Sometimes they torture it in horrible ways and it behaves in some strange and unexpected manner.... at which point, it's back to the drawing board."Study groups in nanotechnology have established themselves at universities such as M.I.T. and the California Institute of Technology. "It's captured the imagination of bright, young scientists and engineers," says William A. Goddard III, a professor of chemistry and applied physics at Caltech. Goddard, an admirer of both Drexler and Merkle, occasionally works with them on simulations of molecular machine parts."
Back to Drexler, biased adjectives, hints and innuendoes."Drexler and his nanoist disciples view molecular nanotechnology as a grand challenge of science and technology. And they comb the pages of journals such as Science and Nature for evidence of research advances that might lay the groundwork toward the ultimate self-replicating assembler. At the Foresight conference last fall, Merkle showed a schematic chart illustrating how the current work being done at a scale below 100 nanometers by chemists and materials scientists might one day lead to nanomachines. Lines on the left of the chart represented experimental approaches, such as probes that can manipulate atoms, tubes of graphite about a nanometer in diameter, and novel types of proteins. On the right side resided lines that corresponded to computer simulations of molecular machine parts for assemblers. In the center appeared a noticeable gap."
As for the "schematic chart:" I
have been using charts similar to the one at the left for several years
to illustrate the advantages of pursuing a mixed strategy for developing
nanotechnology. The basic idea is simple: neither a purely experimental
nor a purely theoretical/computational approach will be most effective.
The strengths of the two approaches are complementary, and their combined
use will move us towards the goal more quickly than either alone. Scientific
American is advocating a purely experimental approach (which they
term "real nanotechnology") while denigrating the value of computational
and theoretical work. The computational modeling of molecular machine proposals creates a problem for Scientific American: it supports the conclusion that nanotechnology is feasible. Therefore, it's necessary to discredit computational models without actually addressing their substance.Most researchers whose work moves beyond computer simulations and into the laboratory do not view the challenges of nanotechnology as leading toward the goal of nanoists such as Merkle. A number of them, some of whom even capitalize on the "nano" label in promoting their work, pursue a series of more modest objectives. Differences of opinion about Drexlerian nanoism do not prevent the two camps from occasionally rubbing elbows."
A good talk. Whitesides' expertise in self-assembly was evident. Self-assembly is a powerful method of synthesizing a very useful range of structures. The reader should keep in mind that self-assembly is not, by itself, nanotechnology. A simple way of seeing the difference is to note that a diamondoid structure cannot be self-assembled, and that a self-replicating manufacturing system is based on more than just the principles of self-assembly (this is true even for a cell)."Harvard University chemistry professor George M. Whitesides presented a review of his work at the Foresight conference. Whitesides investigates how simple natural objects self-assemble by minimizing thermodynamic instabilities at a surface, such as those between air and water [see "Self-Assembling Materials," by George M. Whitesides; SCIENTIFIC AMERICAN, September 1995]. At the meeting, Whitesides described how he and his colleagues have used self-assembling hydrocarbon molecules, called alkanethiols, to form ordered rows on a gold surface. They have demonstrated how his fabrication method might be used in a process to pattern far thinner circuit lines on a computer chip that can be achieved through conventional lithographic methods. Eventually, self-assembly of small silicon cubes that contain devices that alter information might lead to news methods for manufacturing computer processors."
Another non-statement: self-replication is "science fiction." This statement is made more intriguing by the fact that the planet is covered by self-replicating systems."Whitesides does not see the goal of his work as edging toward the assembler. He distinguishes between his investigations into self-assembling monolayers and the still distant goal of achieving self-assembly by following a coded set of instructions. Biological cells use this latter approach to make copies of themselves, and so would nanoassemblers. 'What makes [Drexler's vision] exciting is self-replication, and at the moment, it is pretty much science fiction,' Whitesides says. 'Even after a fair amount of thought, there's no way that one could see of connecting this idea to what we know how to do now or can even project in the foreseeable future.'"
Present manufacturing methods involve a very big and increasingly expensive thing (a semiconductor fabrication facility) to make a very small and not too expensive thing (a computer chip -- note that silicon computer chips on a per pound basis are quite expensive: hundreds of thousands or millions of dollars per pound). In sharp contrast, we have examples of very small things (cells) that make other very small things (other cells) and do so inexpensively (perhaps a dollar a pound). Nanotechnology proposes to use self-replication to achieve low cost, and certainly does not propose to use something resembling current semiconductor fabrication methods."The complexity of making objects with individual molecular building blocks may eliminate any of the dramatic cost savings envisioned by the nanoists, except in a few clearly delineated technological areas. Fabricating computer chips has already become a form of engineering the small, with the tiniest circuit elements measuring less than a micron. The cost of a new semiconductor plant now reaches into the billions of dollars, in part because of the technical challenges posed by the need to craft ever smaller features onto the surface of a chip. Chipmakers can still justify the added expense because packing circuits more densely lead to higher computational performance and ultimately lower costs. For most other goods, nanotechnologies may receive tough competition from Mother Nature. 'Drexler's grand vision is a nice one, but sometimes some of the specifics are not entirely correct,' comments Jane A. Alexander, who established the nanoelectronics program at the Advanced Research Projects Agency. 'I once heard him say we'd make tables out of nanotechnology. Wood is awfully cheap, and trees do it very nicely.'"
Shortly after Jones made his case, we responded and rebutted his arguments point by point on the web. As Jones was grossly ignorant of the field, this was a relatively straightforward exercise. The existence of this rebuttal was conveniently omitted in Scientific American's story."Keeping every atom in its place may also prove exceedingly onerous at the atomic level. David E. H. Jones, a researcher in the department of chemistry at the University of Newcastle upon Tyne, who may be best known as the author of the irreverent "Daedalus" column in Nature, has provided a pointed critique of the idea that individual atoms and molecules could serve as construction elements in the ultimate erector set. Jones made his case a year ago in a review of a popular book about Drexler by science writer Ed Regis, called Nano. Regis's account generally treats the chief nanoist's ideas favorably."
This issue was specifically addressed in the rebuttal. Briefly (a) he has confused the concept of "atomically precise" with the method of manufacture, (b) proposals that call for the use of highly reactive compounds also call for an inert environment, such as vacuum or a noble gas, and (c) some specific reactions that involve single atoms, such as the hydrogen abstraction tool discussed earlier, have been modeled both with ab initio quantum chemistry and molecular dynamics. It is obvious from reading Jones' comments that he was literally unaware of this body of work."Jones describes the contortions often required to achieve atomic control of matter. In 1989 two IBM researchers penned their employer's acronym by manipulating 35 xenon atoms with a scanning tunneling microscope - a device that dragged the atoms across a nickel surface. The atoms moved because of chemical bonding interactions that occurred when the microscope's tungsten tip came to within a tenth of a nanometer or so of each atom. Jones notes the difficulties involved: The IBM logo was created in an extremely high vacuum at the supercooled temperature of liquid helium using inert xenon atoms. Outside this rarefied environment, the world becomes much less stable. 'Single atoms of more structurally useful elements at or near room temperature are amazingly mobile and reactive,' Jones writes, 'They will combine instantly with ambient air, water, each other, the fluid supporting the assemblers, or the assemblers themselves.'"
This was the summing-up paragraph of Jones' book review. As he stated these various problems in the earlier paragraphs, and as we responded paragraph by paragraph to his arguments, we here refer the reader to our response. A brief discussion of a method for dealing with the positional uncertainty caused by thermal noise in the context of an assembler is available."Jones believes that the nanoists fail to take into account critical questions about the thermodynamics and information flow in a system of assemblers. 'How do the assemblers get their information about which atom is where, in order to recognize and seize it? How do they know where they themselves are, so as to navigate from the supply dump [where raw atomic material is stored] to the correct position in which to place it? How will they get their power for comminution [breaking up material] into single atoms, navigation and, above all, for massive internal computing?' The list continues before Jones concludes, 'Until these questions are properly formulated and answered, nanotechnology need not be taken seriously. It will remain just another exhibit in the freak show that is the boundless-optimism school of technical forecasting.'"
The response was a point-by-point rebuttal that Scientific American was aware of and chose not to mention. A charitable attitude towards this omission might be that they simply didn't know about its existence. Unfortunately for this hypothesis, Scientific American made extensive use of resources on the web (I know -- I spent more time than I care to remember on the telephone discussing the contents of specific web pages with them). Further, when they asked for a critic, I provided them with Jones' name and suggested they look at my web page rebutting his arguments. I followed up this discussion by sending them an e-mail which said: "David Jones ... wrote a review of "Nano!" in Nature that was rather bluntly critical. I don't think much of his opinions, but I don't think he's retracted them. There's a link to my comments from the "reactions" page, along with the reference to his article.""The nanoists' response to this fusillade is simple: read Drexler's technical tome Nanosystems, which contains a response to virtually any general point raised by detractors. Acoustic waves, for example, can be used to supply power to assemblers, an answer to one of Jones' objections."
As a general rule of thumb, groups or individuals that have an interest in nanotechnology have long planning horizons. NASA, for example, often plans missions many years or even decades in advance. Members of the National Space Society typically view the settlement of space as a multi-decade undertaking. The Department of Defense has internal planning documents, such as the Project 2025 report, that consider where the world might be, both politically and technically, 30 or more years from now. Medical applications of nanotechnology are of interest to individuals if they can be developed within their lifetime: many of us expect to live at least a few more decades. Many people care about the world that their children will live in. Members of the environmental movement want to preserve the beauty and majesty of nature not only for the next year or two, but for centuries and more. It's not surprising, therefore, to see interest in nanotechnology from members of these groups."Drexler contends that his critics, with their need to focus on new products or the next grant-funding cycle, have trouble thinking far enough into the future. 'To people outside who don't understand that you're talking about the year 2020 or whatever, these ideas raise confused, unrealistic expectations about the short term,' Drexler maintains. 'That makes researchers uncomfortable because it's not a yardstick they want to be measured by. It also brings in ethics and the future of the human race, which are not the usual cool, scientific, analytical concerns.'"
I believe a "hard-nosed" engineer, pretty much by definition, would have a planning horizon of under 5 years. In order to motivate such individuals it is necessary to either (1) describe something that they can do in the next few years that will provide them with some direct benefit (a product that makes money, for example) or (2) pay them money to work on something that will not have any significant pay-back in 5 years."For engineers who build things, finding the relevant page in Nanosystems is not enough. Drexler touts his work as 'theoretical applied science': research constrained only by physical law, not by the limits of present-day laboratory or factory manufacturing capabilities. To hard-nosed engineers, though, the juxtaposition of 'theoretical' and 'applied' quickly becomes an oxymoron. Their response to the author of Nanosystems? Come back when you can tell me how to make those things."
So far, the critics have provided no unanswerable (or even very difficult) problems -- small or otherwise -- to accumulate. Barth's concern that intermediate structures must be stable is a significant design constraint -- just as the concern that the intermediate states of (say) a house must be stable is also a significant design constraint. It might be prudent to assemble a wall before trying to raise it, and the roof should presumably be put in place after there are adequate supports to hold it. The argument that nanotechnology is infeasible because the stability of intermediate structures imposes a design constraint is remarkably weak, particularly when we consider the astronomically large number of intermediate structures that are possible if we wish to make a structure of any reasonable size."The accumulation of small details may doom the best theories for small machines. Phillip W. Barth, an engineer at Hewlett-Packard, characterizes simulations of molecular bearings as 'computer-aided speculation.' 'The holes are bigger than the substance,' he says of Nanosystems. 'There's a plausible argument for everything, but there are no detailed answers to anything.' Barth is a leading engineer in micromechanics, a field that builds microscopic sensors and machines from silicon [see "Silicon Micromechanical Devices," by James B. Angell, Stephen C. Terry and Phillip W. Barth; SCIENTIFIC AMERICAN, April 1983]. Barth observes a lack of discussion of a number of basic engineering considerations that could make many of Drexler's nanodevices impossible to build. Drexler's nanobearings may be molecularly stable. But Nanosystems, he notes, does not address the stability of structures synthesized during intermediate steps in building the bearings."
An interesting series of statements. Energy is indeed important, but providing a source for it is "no good?" Followed by the implied claim that we're providing perpetual motion? To think that Drexler and myself; the researchers at Caltech, Oak Ridge, NASA Ames, NRL, NCSU and elsewhere; the students at MIT, Caltech, and other universities; and the many others who have looked over the proposals for molecular machines; would have anything to do with a proposal that either required or provided perpetual motion is not only insulting, it's ... very ... very ... dumb! Though not all that unusual for this story."Unresolved details, moreover, may not be so trifling. 'Energy is a fundamental concern,' Whitesides declares. 'It is no good to say it comes from somewhere - acoustic waves or whatever. If we can forget the details of energy supply, we have a perpetual motion machine.'"
Being charitable, however, perhaps there is a concern
about how to convert mechanical energy into chemical energy. A simple example
of a mechanosynthetic process to do this is the conversion of a precursor
to the hydrogen
abstraction tool to the activated form. Consider the precursor shown
to the left. Clearly, if we pull hard enough on the two handles, something
will break. If we design in a "weak link," then it will break
where we want it to break -- in this case, between the silicon and carbon.
The result is the activated hydrogen abstraction tool, which is chemically
very reactive. It's useful to recall, at this point, that the original question was whether or not nanotechnology, defined as the ability to inexpensively make most structures that are consistent with natural law, is or is not feasible. There are very good reasons to believe that it is. The relevance of Marxism and Christianity to this technical question is, shall we say, unclear. The inclusion of random quotes to "bolster" this red herring serves little useful purpose."The present inability to build an assembler - coupled with elaborate speculation about what the future may hold - gives nanotechnology a decidedly ideological or even religious slant, in Barth's view. In early January he posted a message to an Internet bulletin board (sci.nanotech) suggesting that subscribers comment on whether molecular nanotechnology has the makings of a mass social/political movement or a religious faith in the traditions of Marxism or Christianity. Barth bolsters the case for nanoism as a form of salvation by citing a passage from a new magazine called NanoTechnology: 'Imagine having your body and bones woven with invisible diamond fabric. You could fall out of a building and walk away.'"
Again, the objective is to draw attention away from the technical issues. Space travel is feasible even if not all science fiction stories about space travel are correct or even sensible.The nanoists' legacy may be to stoke science-fiction writers with ideas for stories. The latest genre in science fiction employs nanotechnology as its centerpiece. A follow-on to the cybernetic fantasies of authors such as William Gibson, it is sometimes even called "nanopunk." The world depicted by nanowriters goes beyond cybernetic mind control and downloading one's brain into a computer. It postulates ultimate control over matter. "It seems like nanotech has become the magic potion, the magic dust that allows anything to happen with a pseudoscientific explanation," says Ist-van Csicsery-Ronay, Jr., an editor of the journal Science-Fiction Studies, published by DePauw University."
Drexler's comment about sums it up."A collection of 'nano' stories that appeared last year features the imaginings of noted science-fiction writers, such as Poul Anderson. The volume, Nanodreams, even contains an introductory essay by Drexler on the merits of science fiction as a means of exploring the societal implications of a nanotechnological future. 'Saying something sounds like science fiction should not be regarded as a form of dismissal,' Drexler said in a recent interview. 'Much of what science-fiction writers described in the 1950s happened, and you need to distinguish between antigravity and flying to the moon, between time travel and making a robot that works in the factory.'"
And the relevance of this to the technical feasibility of nanotechnology is?"Nanodreams includes a story in which the pain experienced by a fetus during an abortion is telecommunicated to nanomachines that reproduce the sensation within the father of the child - and then, finally, kill him. Another nanotale describes a company that has just achieved a breakthrough by making nanomachines that can repair tissue damaged by a bullet wound. In one scene a poster on a laboratory wall depicts Albert Einstein handing a candle to Drexler."
More biased language. How would someone from 1896 react to what is common place today?"The fantasies of nanoists posted on Internet bulletin boards and World Wide Web sites often outstrip the imaginings of the best science-fiction writers. Take the often discussed idea of a utility fog: nanobots that link together to create materials and objects in a desired form and shape, from paint to furniture. 'When you got tired of that avant-garde coffee table, the robots could simply shift around a little, and you'd have an elegant Queen Anne piece instead,' reads one description on the Web."
Another non-statement. If we eliminate the statements in the story that have no bearing on the technical issues, most of the story simply vanishes. The few statements that remain are easily rebutted."Chemistry has distant roots in alchemy, the belief that transmutation of materials will bring health and wealth (though perhaps not ultimate mastery of interior decoration). Nanoism resembles a form of postmodern alchemy - and one that awards cash for molecular machine parts. Toward the end of November's Foresight conference, an announcement was made about a new prize, named for Feynman."
Historically, prizes have been very effective at motivating research in a field."The prize of $250,000 comes courtesy of Jim Von Ehr, an executive at Macromedia, a software company in San Francisco, and Marc Arnold, a St. Louis venture capitalist. It is to be awarded for the fundamental breakthroughs that will usher in the era of molecular nanotechnology: a robot arm and a computing component for an assembler."
As the reader might appreciate, the kind of ad hominem attacks used in this story would make anyone tired. The fact that researchers pursuing fundamentally new and valuable objectives commonly have to endure such an ordeal is a societal problem of great significance. How many discoveries were not made, or were delayed, because the people in a position to make them decided it just wasn't worth the pain?"For the time being, the nanoists can only wait for these breakthroughs to arrive, while continuing to formulate their computerized models of molecular machine parts. It may be a long time coming. In fact, Drexler himself has said that his fortitude has been weakened by jibes from critics and that he might consider a calling other than nanotechnology. "I'm tired of it," he says."
Scientific American has another major problem with Feynman. If Feynman is taken at face value, then nanotechnology should be feasible. Jones mentioned this as one of the arguments in favor of nanotechnology but then dropped the subject, never explaining either (a) where Feynman was wrong or (b) why Feynman's observations were inapplicable."Nanoists' convictions about the inevitability of a breakthrough evoke memories of another idea once posed by Feynman, their adoptive mentor. In a commencement speech given to the 1974 graduating class at Caltech, Feynman noted that some Pacific Islanders religiously awaited the return of the U.S. troops who had landed in World War II. He described the elaborate preparations the islanders made for the return of the planes that would bring them advanced technological accouterments and limitless wealth. Fires mark the sides of the runways. A man plays air-traffic controller by sitting in a hut with carved wooden headphones from which pieces of bamboo stick out, like antennas. The believers wait patiently in this preindustrial imitation of an airfield."
I think Feynman would not be pleased to have his name and words attached to this technically empty argument. Readers are invited to read There's plenty of room at the bottom and draw their own conclusions."'They're doing everything right,' Feynman said. 'The form is perfect. It looks exactly the way it looked before. But it doesn't work. No airplanes land.' Similarly, some scientific endeavors rely on wish fulfillment - and an inability to consider why something may not work, Feynman noted. 'So I call these things cargo cult science,' he concluded, 'because they follow all the apparent precepts and forms of scientific investigations, but they're missing something essential, because the planes don't land.' Until the nanoists can make an assembler and find something useful to do with it, molecular nanotechnology will remain just a latter-day cargo cult."
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