Did Smalley deliver a killer blow to Drexlerian MNT?

The most high profile opponent of Drexlerian nanotechnology (MNT) is certainly Richard Smalley; he’s a brilliant chemist who commands a great deal of attention because of his Nobel prize, and his polemics are certainly entertainingly written. He has a handy way with a soundbite, too, and his phrases “fat fingers” and sticky fingers” have become a shorthand expression of the scientific case against MNT. On the other hand, as I discussed below in the context of the Betterhumans article, I don’t think that the now-famous exchange between Smalley and Drexler delivered the killer blow against MNT that sceptics were hoping for.

For my part, I am one of those sceptics; I’m convinced that the MNT project as laid out in Nanosystems will be very much more difficult than many of its supporters think, and that other approaches will be more fruitful. The argument for this is covered in my book Soft Machines. But, on the other hand, I’m not convinced that a central part of Smalley’s argument is actually correct. In fact, Smalleys line of reasoning if taken to its conclusion would imply not only that MNT was impossible, but that conventional chemistry is impossible too.

The key concept is the idea of an energy hypersurface embedded in a many-dimensional hyperspace, the dimensions corresponding to the degrees of freedom of the participating atoms in the reaction. Smalley argues that this space is so vast that it would be impossible for a robot arm or arms to guide the reaction along the correct path from reactants to products. This seems plausible enough on first sight until one pauses to ask, what in an ordinary chemical reaction guides the system through this complex space? The fact that ordinary chemistry works one can put a collection of reactants in a flask, apply some heat, and remove the key products (hopefully this will be your desired product in a respectable yield, with maybe some unwanted products of side-reactions as well) tells us that in many cases the topography of the hypersurface is actually rather simple. The initial state of the reaction corresponds to a deep free energy minimum, the product of each reaction corresponds to another, similarly deep minimum, and connecting these two wells is a valley; this leads over a saddle-point, like a mountain pass, that defines the transition state. A few side-valleys correspond to the side-reactions. Given this simple topography, the system doesnt need a guide to find its way through the landscape; it is strongly constrained to take the valley route over the mountain pass, with the probability of it taking an excursion to climb a nearby mountain being negligible. This insight is the fundamental justification of the basic theory of reaction kinetics that every undergraduate chemist learns. Elementary textbooks feature graphs with energy on one axis, and a reaction coordinate along the other; the graph shows a low energy starting point, a low energy finishing point, and an energy barrier in between. This plot encapsulates the implicit, and almost always correct, assumption that out of all the myriad of possible paths the system could take through the hyperspace of configuration space the only one that matters is the easy way, along the valley and over the pass.

So if in ordinary chemistry the system can navigate its own way through hyperspace, whats different in the world of Drexlerian mechanochemistry? Constraining the system by having the reaction take place on a surface and spatially localising one of the reactants will simplify the structure of the hyperspace by reducing the number of degrees of freedom. This makes life easier, not harder surfaces of any kind generally have a strong tendency to have a catalytic effect but nonetheless, the same basic considerations apply. Given a sensible starting point and a sensible desired product (i.e. one defined by a free energy minimum) chemistry teaches us that it is quite reasonable to hope for a topographically straightforward path through the energy landscape. As Drexler says, if the pathway isnt straightforward you need to choose different conditions or different targets. You dont need an impossible number of fingers to guide the system through configuration space for the same reason that you dont need fingers in conventional chemistry, the structure of configuration space itself guides the way the system searches it.

This is a technical and rather abstract argument. As always, the real test is experimental. There’s some powerful food for thought in the report on a Royal Society Discussion Meeting “‘Organizing atoms: manipulation of matter on the sub-10 nm scale'” which was published in the June 15 issue of Philosophical Transactions. Perhaps the most impressive example of a chemical reaction induced by physically moving individual reactants into place with an STM is the synthesis of biphenyl from two iodobenzene molecules (Hla et al, PRL 85 2777 (2001)). To use their concluding words “In conclusion, we have demonstrated that by employing the STM tip as an engineering tool on the atomic scale all
steps of a chemical reaction can be induced: Chemical reactants can be prepared, brought together mechanically, and finally welded together chemically. ” Two caveats need to be added: firstly, the work was done at very low temperature (20 K) presumably so the molecules didn’t run around too much as a result of Brownian motion. Secondly, the reaction wasn’t induced simply by putting fragments together into physical proximity; the chemical state of the reactants had to be manipulated by the injection and withdrawal of electrons from the STM tip.

Nonetheless, I rather suspect that this is exactly the sort of reaction that one would say wasn’t possible on the basis of Smalley’s argument.

(Links in this post probably need subscriptions).

Nanotechnology at the British Association

The annual British Association meeting is the main science popularisation event in the UK, and not surprisingly nanotechnology got a fair bit of attention this year. The physics section ran a session on the subject yesterday morning. First up was Nigel Mason, who organised the physics part of the meeting this year and thus could give himself the best slot. He’s an atomic and molecular physicist who does scanning probe microscopy; his talk was a standard account of nanotechnology from the point of view of someone who’s got a scanning tunneling microscope and knows how to use it; from Feynman via the IBM logo and quantum corrals to some of his own stuff about imaging DNA. Next was Mark Welland, who runs the Nanotechnology Centre at Cambridge University. Once he’d calmed down after the first talk, which had upset him in all sorts of ways, not least by talking about Drexler in what he thought was an insufficiently critical way, he talked about his group’s work on silicon carbide nanowires, which if they do nothing else have produce some of the prettiest images to come out of current nanoscience. Then it was my turn. As Mark Welland said, making his excuses for leaving early, “I know what you’re going to talk about because I’ve read your book“.

Harry Kroto, Nobel Laureate for his co-discovery (with Richard Smalley) of buckminster fullerene, was talking about nanotechnology in the chemistry section in the afternoon, but I didn’t get a chance to see it as I was roped into a rather tedious panel discussion about how the public perceives physicists. The final event for me was an appearance in a discussion event compered by the (excellent) BBC radio science journalist Quentin Cooper. This brought me the chance to share a platform with a poet, a paleontologist, and the government’s chief scientific advisor, Sir David King. We also got some free beer, though to Sir David’s horror this was bottles of (american) Budweiser rather than pints of bitter. So I got a final chance to make my nanotechnology pitch, though Quentin Cooper was rather more interested in trying to prise an unwise comment from the famously undiplomatic King. He happily confirmed that he still thought that global warming was a bigger threat than terrorism, he didn’t deny the suggestion that he’d received a rebuke from 10 Downing Street for saying this in the USA , where it’s language not thought suitable for a servant of the government of a loyal ally, and he was smilingly gnomic about who he wanted to win the US presidential election.

The BA is all about publicity, so it’s worth asking how much interest this attention to nanotechnology stirred up. For my part, I think my talk got a good reaction, I signed the first copy of my book for a stranger, I did an interview for Radio New Zealand, and got the approval and interest of one of the BBCs best science journalists. And I now know who’s reviewing my book for Nature (Mark Welland). But I don’t think the subject really caught fire. Maybe a rather febrile summer of nanotechnology coverage has left media people starting to be a tiny bit bored with the word.

Not Enough (Yet)

I’ve just finished reading Enough, Bill McKibben’s jeremiad against genetic engineering, robotics and nanotechnology. The argument, as suggested in the title, is that we’ve done enough science, and we should stop developing nanotechnology and genetic engineering now, before we lose irrecoverable aspects of our humanity. It’s an important book, a compelling book in some ways, and I’m surprised by how much I agree with it. I accept a lot of McKibben’s arguments about what it is to be human, and like him I find that the posthumanists’ creed that we should happily trade in our humanity for some ill-defined post-human nirvana very unattractive.

I part company with McKibben at the point where he dismisses the claim that we need better science and technology to improve our current human condition. It’s easy, as McKibben does, to find anecdotes about the way in which, say, high technology agriculture has made the lives of third-world farmers worse rather than better. But another excellent book from my summer reading list – Enriching the Earth, by Vaclav Smil, makes it clear how much humanity as a whole depends on intensive agriculture, and in particular on artificial nitrogen fertilizers. For privileged inhabitants of rich countries, like myself and Bill McKibben, a rich diet based on non-intensive farming is entirely possible and indeed very agreeable. But for the majority of the world’s city dwelling population this simply isn’t an option. Smil’s book lays out the figures – non-intensive farming, without artificial fertilisers, could supply only 40% of the world’s current population at current average diets, a figure that would rise to 50% if everyone adopted a minimally nutritious but frugal diet.

This is just one example of the way in which we are currently existentially dependent on technology for the survival of the human race at current population levels. But the technology we depend on is not sustainable and has many well-known disadvantages – taking this example, artificial fertilisers are produced using a huge amount of fossil fuel based energy, with serious negative consequences like global warming, and the direct consequences of waste nitrogen fertiliser run-off on ecosystems are now well known. The world population is now starting to level off, and we do have it in our grasp to have a future in which the world has a stable population with a decent standard of living, obtained in a sustainable way. But to get to this point the technology we have now is not enough. We’ll need clean energy, clean water, better medicine, ways of cleaning up the environment and keeping it unpolluted. Nanotechnology should play a big role in all these developments.

A grand day out

I’ve been to London today, for two meetings, both about nanotechnology but with rather contrasting flavours. The morning saw me at a large TV production company, which is planning a three part series on nanotechnology for a national broadcaster. In the afternoon I was at the Department of Trade and Industry, with a couple of social science colleagues, including Stephen Wood, my coauthor on the ESRC report The Social and Economic Challenges of Nanotechnology. We were meeting the civil servant in charge of the DTI nanotechnology agenda, together with Hugh Clare, who is the director of the Micro/Nanotechnology network that the DTI is trying to establish with its 90 million, to discuss how they would like to see the social science research agenda shaped.

This was an interesting glimpse into government thinking. While the Treasury lives by a rigorous creed of free markets and non-intervention, the DTI is doing its best to formulate and implement what’s very reminiscent of an old-fashioned industrial policy, using government-sponsored innovation to rescue the small remnants of the UK’s manufacturing industry, for which these mandarins showed rather a touching nostalgia. What worries me is the central problem of how you define nanotechnology. The DTI is very keen on network building, but these networks are self-selecting and not necessarily truly representative. If you put together a network, how do you know that these are the companies and organisations that are genuinely developing and using nanotechnology to make new products and businesses, rather than those that find nanotechnology a useful label for marketing or fund-raising purposes? Here’s where the kind of network analysis that social scientists are building could be really helpful.

How about the public perception issue? This is something that clearly deeply bothers the DTI, and there was palpable relief at the Royal Society report; clearly they were very comfortable with the modest extensions of regulation proposed in the report, and they seemed pretty confident that the government would simply accept the report and implement it in full. They’re seriously worrying about over-regulation driving not just manufacturing but research overseas, and they cite the example of the relocation of animal experimentation to Hungary. But again, I don’t sense much confidence about what to do with the public perception issue. Clearly no-one in government believes in the so-called “deficit model” of public engagement anymore. (This is the idea if that you simply explained everything clearly enough the scales would fall from the public’s eyes and they would eagerly embrace whatever new technology you were offering). Old fashioned views about risk analysis won’t wash either – you can produce as many risk tables as you like to demonstrate that crossing the road is quantitatively more dangerous than using a nuclear powered toaster to make your genetically modified toast, but if this conflicts with people’s deep intuitions they’ll trust the intuition.

I think it all boils down to visions, and this where I connect with my morning meeting. A company making a TV program for prime-time isn’t going to devote three slots to potential improvements in supply chain management, better impact toughness for engineering thermoplastics, and new avenues in textile treatment. It’s the big visions that are going to make popular TV, and at the moment its the environmentalists, on one hand, and the Drexlerites, on the other, that have those visions, deeply uncomfortable as those visions are to the sober people in government departments and the nanobusiness world. But people need those big narratives to make sense of and get comfortable with technological change, and if people don’t like the narratives that are on offer they’d better develop a compelling one of their own.

Drexler and the nanosubmarines

I wrote below about Drexler’s unhappiness that I had illustrated my article in Physics World with a particularly
silly image of a nanosubmarine. He wrote that could not be held responsible for the “ridiculous artists concepts” that have become associated with his work, and thus my criticism of the nanosubmarine illustration wasn’t a fair criticism of MNT. I’m quite sure that if Drexler had been directly involved in the production of images like these, then they would be much more physically plausible. But I wonder if the supporters of Drexler have been as quick to seek correction when these images are used in connection with articles that are positive about MNT? The particular image I chose is very widely circulated, as it appears on the Microsoft Encarta online encyclopedia with the caption “Nanobot computers of the future” . Many readers – particularly high school students – will regard this source as authoritative, and it is perhaps a pity that this image remains unchallenged there.

The neutral onlooker might also find it puzzling that exactly the same image appears on the website of the Foresight Institute, of which Drexler is Founder and Chairman Emeritus. Of course, Drexler can’t be held responsible for everything on this large website, particularly given that he has no executive role. But the casual browser must surely be forgiven for thinking that images on the Foresight website carried some kind of endorsement from the Foresight Institute, and thus by extension from its Board chairman.

But the issue of the use of imaginative images is far from black and white. I gave a talk at a conference in May in which I made similar criticisms of this kind of image, and I was surprised to be taken to task about it by a prominent member of the UK nanobusiness community. His argument was that I should consider the image as a metaphor, and if the public found it easier to understand the image of a nanobot vacuum cleaner sucking up cholesterol deposits than a more realistic picture of, say, an anti-cholesterol drug wrapped up in an advanced nanoscale drug-delivery device like a liposome, then the imaginative image served a valuable purpose. Perhaps I’m too literal minded to buy this argument. The message must surely be that visual metaphors are very powerful, but if not used carefully they can rebound in unexpected and unwelcome ways.

An international dialogue on the responsible development of nanotechnology

Science administrators from 25 governments and the EU met a couple of months ago to discuss how the responsible development of nanotechnology should be managed globally. The report of the meeting is now publically available.

One of the most impressive things about the meeting is the attendance list; from the USA Mihail Roco from the National Nanotechnology Initiative, Undersecretary of State for Science and Technology Phil Bond, and the Presidential Science Advisor John Marburger III, and correspondingly significant representation from almost every other country with a significant research and development effort in nanotechnology. This essentially amounts to the developed countries of Europe and the Pacific Rim, and in the developing world South Africa, India and the big economies of Latin America. The glaring absentee was China, presumably because Taiwan was strongly represented.

The themes discussed were the now-familiar ones of health and safety, possible environmental impacts, ethical implications particular at the interface with medicine and the life sciences, and special factors that might impact on developing countries.

As to the primary question of what nanotechnology actually is, I read with approval this paragraph…
“Numerous participants stressed that it was important not to think of nanotechnology as a single technology, but rather of a number of both discreet and interrelated technologies, each of which will have their own risk/benefit profile. It was suggested that it would be helpful to develop some sort of a framework within which important distinctions can be made such that the discussion of responsible R&D of nanotechnology does not become overly broad, and result in sweeping but not very meaningful statements and actions.”

MNT devotees will be disappointed to see their visions dismissed by John Marburger thus:
“Science fiction, some of it quite entertaining as literature, appears to be a major factor in the public perception of nanotechnology. Unfortunately, the entire field acquired a cult-like following in the 1990’s that includes many engineers and scientists who have personal visions about the revolutionary possibilities of nanotechnology. These visions are good for motivating work, but are not scientifically validated. This is a relatively common phenomenon in science, whose function is to match grand dreams against the harsh reality of Nature. We need dreams, visions — and perhaps even fears — in the first place to drive the arduous business of scientific investigation, but we may not assume their validity, nor should we act carelessly upon them as we plan to invest society’s scarce resources.”

Wiggly widgets in Small Times

A piece by Candace Stuart in Small Times gives a review of my book “Soft Machines”. I suppose that the publicist in search of a line for a book cover would choose the description of the book as “a rich and satisfying full-course meal” and the academic in me might approve of the line “This is not nano lite”, but I’m mostly pleased that the reviewer seems to have read the book and appreciated the main message.

Making me a better human

An interesting article on the Better Humans website, Unraveling the Big Debate over Small Machines, quotes me, and adds that my position on nanotechnology isn’t very different to Drexler’s. This is at first sight rather puzzling since my recent article in Physics World, The Future of Nanotechnology, and indeed my book Soft Machines, have been read by many people, including Drexler himself, as attacks on the Drexlerian position. Indeed, I would say myself that my views are actually pretty similar to those of MNT arch-sceptic George Whitesides, though I possibly express them a bit more politely, and with a little less self-confidence.

But on reflection, I find this rather a welcome perception. Perhaps it does mean that a space is growing on both sides of the debate for some rather more nuanced positions than we’ve seen in the past. The Better Humans article gives a lot of attention to the Drexler-Smalley debate. It seems to me that we need to move on from this. MNT sceptics need to recognise that Smalley did not deliver the knock-out punch that they were hoping for. This was brought home to me in Santa Barbara this week in a conversation with an old friend who teaches a sophomore class in nanotechnology at the University of Pennsylvania. She’d set her class the task of studying the debate and deciding which side they thought had prevailed; an overwhelming majority favoured Drexler. So a reasonable sample of educated and intelligent young people was not convinced by Smalley. On the other hand, I think that MNT devotees are wrong to think that this means there are now no rational grounds for scepticism about MNT. While the possibility of some kind of radical nanotechnology is proved by the existence of biological nanomachines, the question of what the best approach to making synthetic nanomachines is is by no means decided. My book Soft Machines argues that MNT has many more disadvantages and potential difficulties than some of its supporters admit, and it will be interesting to see whether its arguments prove more convincing than Smalley’s.

Bad news for lab rats

Thanks to Howard Lovy for using a quote from me in his Wall Street Journal article. The article was about reactions to the Royal Society report on nanotechnology, Nanoscience and nanotechnologies: opportunities and uncertainties, and my quote said something like: “Good news for the environment, good news for nanotechnology, bad news for lab rats”. Underneath this flippant sounding response there is, I think, a serious point aboout the way the report marked the emergence of a strange alliance between nanoscientists and environmentalists. The effect of this unlikely alliance has been to focus the nanotechnology debate almost exclusively on a single topic, the possible toxicity of nanoparticles, and certainly the headline reactions to the report have been to focus on its recommendations for tightened regulation of the use of nanoparticles and for more research on their toxicity. I’m not saying that it isn’t a good idea to do both of these things; it is, and the measures the report calls for are entirely sensible. But you don’t have to be a fervent devotee of Drexlerian MNT to wish that the report, and more importantly the press reaction to it, had focused a bit more on the longer term, both in terms of potential benefits, and in terms of the more far-reaching social implications raised by issues such as universal surveillance and human enhancement.

What has led to this alliance of convenience? The idea of nanoparticles posing an environmental toxicity risk is of course one that fits very well in the environmental movement’s long running narrative about the chemical industry, so that’s an issue they are very comfortable about highlighting. The reason for reaction of the nanoscientists is more interesting. The issue is very contained, very tractable, and rather easy to suggest remedies for – a bit more regulation and a few more rats sacrificed in toxicology studies. And from an academic point of view, the subject is a little bit boring. The glamorous areas of nanoscience – the ones that get papers in Nature and Science – are in areas like molecular electronics, biological molecular motors, new applications of nanomagnetism, and suchlike. Making nanoparticles is now really a chemical engineering issue, so mainstream nanoscientists may not be that bothered if a few more obstacles are thrown in its commercialisation path.

A nearly nano-free week in California

I’ve been in Santa Barbara, CA, this week, finding out that traveling with two small children doesn’t leave much time for writing about nanotechnology or anything else. The occasion for the visit is the 65th birthday of Ed Kramer, a distinguished materials scientist at University of California Santa Barbara; it’s a part social, part scientific event bringing together his past and present graduate students, postdocs, and collaborators to celebrate his career so far and to thank him for his huge influence on our scientific careers (I was a postdoc with him between 1987 and 1989 at Cornell; these were two tremendously productive, educational and enjoyable years).

The scientific part of the proceedings consisted of a meeting with talks by his former students and collaborators. There were many nano-science luminaries around and much great stuff talked about; among those talking were Ned Thomas, director of the Institute of Soldier Nanotechnology at MIT, talking about photonic crystals, Herbert Hui with a beautifully lucid description of exactly why gecko feet are so sticky, Chris Ober from Cornell talking about new resist materials for making sub-30nm features, as well as rapid 3-d prototyping at the micron-scale using two-photon photo-polymerisation, and lots of other good stuff too.

Strangely, though, there was little mention of the nano word. Even the most distinguished of our number, faced with giving a talk in front of Ed, felt a bit like a graduate student again, in awe of the great man. Everyone has worked with him is in agreement that he’s someone who expects a lot from their students, who is quick to appreciate good work, and outstanding at standing back and making sure his collaborators get all the credit they deserve and more. But he’s got a low tolerance threshold for hype and fashion and we all knew that the way to get his approval is by telling a solid science story without any sweeping claims for grander significance.

I think we were all overcompensating. I asked Ned Thomas how he felt about now being very publicly labeled as a nanotechnologist, rather than as a polymer physicist. He thought there was a real difference; the science he did was rather similar, learning how to create nanostructures in polymers by self-assembly, but the focus had changed. It wasn’t so much that all his work now was focused on an immediate application, but the possibility of an eventual application provided a much more powerful steer on the direction of his work than was the case in the past. I think this rings true as a description of one of the changes in the sociology of science that nanotechnology as a concept has brought about.