Molecular nanotechnology, Drexler and Nanosystems – where I stand

For the convenience of new readers of Soft Machines, here’s a quick summary of my personal positions on the question of the feasibility of the variety of nanotechnology proposed by Dr K. Eric Drexler in his book Nanosystems. Many of the arguments are made in my book Soft Machines; I’ve discussed some of these issues in my blog in the last few months, and I’ll get round to going into more detail about some of the others in the New Year.

  • Will it be possible to make functional machines and devices that operate on the level of single molecules?
    Yes. As pointed out by Drexler in his 1986 book Engines of Creation, Nature, in cell biology, gives us many examples of sophisticated machines that operate on the nanoscale to synthesise new molecules with great precision, to process information and to convert energy. We know, therefore, that radical nanotechnology (using this term to distinguish these sorts of fully functional nanoscale devices and machines from the sorts of incremental nanotechnology involved in making nanostructured materials) is possible in principle; the question is how to do it in practise.
  • Do the proposals set out in Drexler’s book Nanosystems offer the only way to achieve such a radical nanotechnology?
    Obviously not, since cell biology constitutes one radical nanotechnology that is quite different in its design principles to the scaled-down mechanical engineering that underlies Drexler’s vision of “molecular nanotechnology”, or MNT. One can imagine an artificial nanotechnology that uses some of the same operating principles and design philosophy as cell biology, but executes them in synthetic materials (as discussed in Soft Machines). Undoubtedly other approaches to radical nanotechnology that have not yet been conceived could work too. In comparing different potential approaches, we need to assess both how easy in practise it is going to be to implement them, and what their ultimate capabilities are likely to be.
  • Does Nanosystems contain obvious errors that can quickly be shown to invalidate it?
    No. It’s a carefully written book that reflects well the state of science in relevant fields at the time of writing. Drexler’s proposals for radical nanotechnology do not obviously break physical laws. There are difficulties, though, of two types. Firstly, in many cases, Drexler used the best tools available at the time of writing, and makes plausible estimates in the face of considerable uncertainty. Since then, though, nanoscale science has considerably advanced and in some places the picture needs to be revised. Secondly, many proposals in Nanosystems are not fully worked out, and many vital components and mechanisms remain at the level of “black boxes”.
  • How easy will it be to implement the vision of diamondoid-based nanotechnology outlined in Nanosystems?
    The Center for Responsible Nanotechnology writes “A fabricator within a decade is plausible – maybe even sooner”. I think this timeline would be highly implausible even if all the underlying science was under control, and all that remained was the development of the technology. But the necessary science is very far from being understood. Firstly, there are important uncertainties about the effect on the proposed mechanisms, based as they are on the scaling down of macroscopic mechanical engineering principles, of ubiquitous features of nanoscale physics such as strong surface forces and Brownian motion. This will be particularly serious for devices intended to work in ambient conditions, rather than at very low temperatures at ultra-high vacuum, and I believe that the problems this will cause are seriously underestimated by proponents of MNT. Secondly, there is currently a huge gap in the implementation pathway. Even proponents of MNT disagree on the best way to reach their goal from our current level of technology. Drexler favours soft and biomimetic approaches (see both Nanosystems, and his letter to Physics World responding to my article), though the means of moving from soft to hard systems remains unclear. Robert Freitas and Ralph Merkle favour a more direct route using diamondoid mechanosynthesis; see the ongoing discussion with Philip Moriarty here for the difficulties that this proposal may face. In conclusion, even if diamondoid-based nanotechnology does not break any physical laws in principle, I believe in practise that it will be very much more difficult to implement than its proponents think.
  • Will the advantages of the diamondoid-based nanotechnology outlined in Nanosystems be so great as to make it worth persisting to overcome these difficulties, whatever the cost?
    This depends what you want to use the technology for. Much of the emphasis from proponents of MNT is on using the technology to manufacture artefacts. But arguably the impacts of nanotechnology will be much more important and far-reaching in areas like information processing, energy storage and transduction, and medicine, where the benefits of diamond as a structural material will be much less relevant. In these areas, evolutionary nanotechnology and other approaches to radical nanotechnology, like soft nanotechnology and bio-nanotechnology, may have a greater impact on a much shorter timescale.
  • If the diamondoid-based nanotechnology proposed in Nanosystems proves to be impossible or impractical to implement, does that mean that nanotechnology will have only marginal impacts on the economy and society?
    Not necessarily. See this post -Even if Drexler is wrong, nanotechnology will have far-reaching impacts – for a discussion.
  • 19 Responses to “Molecular nanotechnology, Drexler and Nanosystems – where I stand”

    1. [...] while some of Smalley’s specific objections don’t hold up in detail, and it is difficult to dismiss the Drexlerian proposals out of hand as being contrary to the laws of n [...]

    2. [...] es. When I get a moment, I will move a version of this summary to a more permanent home. “Molecular nanotechnology, Drexler and Nanosystems – where I stand” is a concise [...]

    3. Nanosystems wasn’t just about diamond-based nanotech. It didn’t have space to go into detail on other covalent solids. But it lays the groundwork for several proposed ways to build covalent solids, including machine-phase deposition, solution-phase selectable-position lattice-building, and folding-polymer synthesis followed by crosslinking.

      Molecular manufacturing isn’t about one material. It’s about combining the deterministic nature of engineering with the digital nature of covalent bonding. That makes it relatively easy to access the nanoscale–including fully automated manufacturing–and to build up from engineered nanoscale devices to macro-scale products.

      For many applications, it’s true, the chemistry used doesn’t matter much. What’s more important is the ability to do engineering design rather than messing with the irreducible mathematical complexity of biology. And of course, there are the bonuses of superlubricity, non-diffusive transport, fast digital logic, anisotropic and heterogeneous structures, and linked deterministic machinery–all of which are possible with or without diamondoid.

      But once you’ve gone this far, it makes sense to use a physically high-performance material and build large high-performance products. The strength of Kevlar, epoxy, and carbon fiber should be easily achievable without sacrificing flexibility and toughness.

      Chris

    4. Philip Moriarty says:

      “Nanosystems wasné─˘t just about diamond-based nanotech. It didné─˘t have space to go into detail on other covalent solids.”

      Chris, the problem is that “Nanosystems” doesn’t go into sufficient detail on diamond-based nanotech let alone mechanosynthesis based on any other covalently bound system. Nevertheless, Drexler made a very good decision to spend so much time discussing diamondoid-based mechanosynthesis in “Nanosystems”: hydrogen-passivated diamond surfaces are one of the few systems where a “(1×1)”, radical- (i.e. dangling bond-)free surface is available for site-by-site modification. See my comments on surface reconstructions under the Mechanosynthesis thread (http://www.softmachines.org/wordpress/index.php?p=50).

      “For many applications, ité─˘s true, the chemistry used doesné─˘t matter much. Whaté─˘s more important is the ability to do engineering design rather than messing with the irreducible mathematical complexity of biology”.

      How can you justify the assertion that the “chemistry used doesn’t matter much” as compared to the engineering design? I have just spent a considerable amount of time discussing Freitas’ proposal for diamondoid mechanosynthesis with you on the basis of the detailed surface physics and chemistry. Do you really believe that issues similar to those I’ve raised for Freitas et al.’s proposal (i.e. due to fundamental surface physics problems) won’t appear in **every system** proposed for mechanosynthesis applications? Regardless of whether we start with polymer-based systems and work towards the low level mechanosynthesis steps or, as Freitas and Markle suggest, we start with the mechanosynthesis steps and work ‘up’, we still need to consider the detailed chemistry that underlies the ‘machine language’ of mechanosynthesis. If you still fail to accept this then we’re unfortunately not making very much progress in our discussion. Nevertheless, I’d like to hear the justification for your assertion that the chemistry doesn’t matter and that the engineering design is more important.

      I look forward to your response to my second letter…

      Philip

    5. Richard Jones says:

      Chris, do you really believe that biology is irreducibly mathematically complex (rather than too complicated for us to understand right now)? I know this position is held by followers of the “theory” of intelligent design, but I don’t think anyone else believes it.

    6. Matt Ellis says:

      Chris,

      How does combining the “deterministic nature of engineering” and the “digital nature of covalent bonding” get us fully automated manufacturing? Maybe I’m misunderstanding you but you seem to be implying that in the second paragraph. Regardless, how do you get “fully automated manufacturing?” To do this it sounds like you need some level of control for 10^23 agents (nanomanipulators or whatever). Philip (or maybe Richard) said the “devil is in the details” as pertains to mechanosythesis. This statement also applies to the systems design as well.

    7. Hal Finney says:

      Richard, you are quoted by Howard Lovy at http://nanobot.blogspot.com/2004/12/stop-worrying-and-learn-to-love.html as saying that “the Drexlerian diamondoid vision probably won’t work”. That seems a little stronger than the position you have taken here. What is your opinion on this question?

    8. Richard Jones says:

      Hal, from a scientific point of view, given that é─˙the Drexlerian diamondoid vision” doesn’t obviously break fundamental physical laws, then the strongest thing one can say against it is that it will be very much more difficult to implement than some of its proponents maintain. From an engineering point of view, the question is not whether it is theoretically possible, but whether it is practical and viable. To judge this, we need to compare its benefits (which we need to judge relative not to the state of technology now, but with the state it will be many tens of years in the future) with the many difficulties that stand in the way of its implementation. I don’t think that it’s going to pass this test of engineering viability.

    9. Chris Gilliard says:

      The interesting thing in this thread is that many people are attacking Drexler’s vision of Diamondiod Nanotechnology. Probably, at the same time, Drexler’s vision is what inspired them to get interested in Nanotechnology in the first place. Even if he was wrong on this one point (which we will know in the next few decades), he still inspired the whole field in the first place. In fact, if it wasn’t for Drexler, this whole blog probably wouldn’t exist. I think that Drexler tries to look at the big picture which is one of the reasons so many people critisize him. As many have pointed out there are a number “black boxes” in Nanosystems, but that’s Drexler’s contribution. You can’t realistically expect one person to answer every single question and publish a blue print to how to do it. A visionary is different from the implementers. Every day, scientists are making Drexler’s vision closer to reality and we just have to sit back and wait for those breakthroughs to happen. But they will happen. Today there are so many technologies that will incredibly alter society as we know it. Even if 10% of the ones being touted pan out, the world will change dramatically. I think for the better.

    10. “Probably, at the same time, Drexleré─˘s vision is what inspired them to get interested in Nanotechnology in the first place…he still inspired the whole field in the first place. In fact, if it wasné─˘t for Drexler, this whole blog probably wouldné─˘t exist.”

      Absolutely, completely not – we need to get beyond the fallacy that Drexler was somehow responsible for inspiring the entire field of nanometre scale science. I started my PhD in 1990. This was 7 years after Binnig, Rohrer et al. published their groundbreaking first scanning tunneling microscopy paper and the same year that Eigler and Schweizer published their breathtaking single atom manipulation paper (the classic “IBM” logo paper). Note that these papers were published a considerable time before “Nanosystems” and neither cite any of Drexler’s earlier work.

      Would this blog exist without Drexler’s work? Absolutely! Does that make “Nanosystems” completely irrelevant? No – it’s an interesting text to study for a systems engineering perspective on nanoscience. Does that in turn make Drexler’s work extremely useful to the nanoscience community (i.e. the physicists, chemists, biologists, and materials scientists involved in manipulating matter at the atomic and molecular levels)? In the vast majority of cases, no. (Freitas, Merkle et al. have carried out some nice theoretical quantum chemistry on mechanosynthetic steps but have yet to propose a coherent strategy as to how those steps might be implemented).

      “Every day, scientists are making Drexleré─˘s vision closer to reality”. As I’ve recently discussed at length with Chris Phoenix (the debate will be posted in its entirety in this blog in the near future), in the 15 years since Eigler et al.’s truly visionary and pioneering work, there has not yet been an experimental demonstration of a single mechanosynthetic step as outlined in Nanosystems. Indeed, I do not know of even one group that is working to implement/demonstrate (in the real world) either basic mechanosynthetic steps or to even get close to Stage 1 of Drexler’s “backward chaining” strategy for molecular manufacturing as outlined in Chapter 16 of “Nanosystems”".

      Drexler’s ideas are certainly interesting and there are no immediately obvious flaws in the physics of “Nanosystems” (although I have discussed a number of scientific issues with Chris Phoenix (debate to be posted)directly related to Nanosystems which have yet to be addressed).But was his work the “genesis” of single atom manipulation and molecular positioning (some of the most exciting areas of state-of-the-art nanoscience)? Definitely – and demonstrably – not.

    11. Chris Gilliard says:

      Phillip, the book “Engines of Creation” and others by Drexler have inspired many people in the Nanotechnology field(s). While, it may not have inspired you, I do believe you are in the minority.

      Also, about the progress being made on Drexler’s vision….I’m not making a specific referance to mechanosynthesis. I believe we are making progress towards the ubiquitous precise control of matter on the molecular level a theme throught Drexler’s writings. One example of this is the Carbon Nanotube and the Chemical Vapor Deposition processes that can be used to create them. This same method can also be used to produce diamond synthetically. Almost every week, I see another major breakthrough in the field. Another example is molecular computing. Molecular computing is progressing at a rapid speed. I just read about a molecular transistor made from nanotubes that operates in the microwave range. You might be asking, “What does this have to do with Drexler?”. Well, for one thing, Richard Smalley, the person who discovered the BuckminsterFullerene (the break through that led to the discovery of Carbon Nanotubes) has said that Engines of Creation is one of the things that inspired him to enter the field in the first place.

      Before Drexler, the miniaturazation field was defined by a speech given by another great visionary “Richard Feynman” in 1959 titled “There’s Plenty of Room at the Bottom”. For it’s time, it was very cutting edge stuff, but if you take a look at it today, you’re tempted to say, “so what?” during certain parts. Drexler took the principals that Feynman laid out and expanded them to explain what is humanly possible carrying this concept to it’s extreme.

      My main point is that even if Drexler’s ideas about “how” we will move into the Nanotechnological era are completly wrong, his vision of “What a Nanotechnological era is?” is a much bigger contribution than any particular step that’s taken on the path to the positional control of matter that I mentioned at the begining of this post. I’m not trying to minimize what scientists in the field do, but evaluating Drexler as a scientist is like evaluating Michael Jordan’s golf game.

    12. Philip Moriarty says:

      Chris,

      “… the book é─˙Engines of Creationé─¨ and others by Drexler have inspired many people in the Nanotechnology field(s). While, it may not have inspired you, I do believe you are in the minority.”

      I think that you’d be very surprised at just how small a percentage of researchers currently working in nanometre scale science have *read* “Engines of Creation”, “Unbounding The Future”, or – in particular – “Nanosystems” let alone been inspired by Drexler’s writings. For example, I have spent quite a few days over the last month in a “Chemical Craftwork” workshop which involved a considerable number of scientists who work on nanoscale problems. Beyond the “grey goo” mythology, the vast majority of these scientists were not aware of Drexler’s work. Similarly, each of the postgraduate students who have worked (or currently work) in the Nottingham Nanoscience group have decided to take up a PhD not on the basis of Drexler’s work but because they were inspired by, for example and amongst a variety of possibilities, STM images of individual atoms, Eigler et al.’s atomic manipulation work, or results related to Kroto, Smalley et al.’s fullerene discoveries. [To date, ~ 30 students (including a considerable number of European students undertaking Marie Curie fellowships) have worked in the Nottingham group].

      Richard Jones and I are, I believe, in a rather small minority as physicists who have invested the time and effort to read “Nanosystems”. As, I’ve mentioned before, it’s an interesting book to read as, for me, it presents an entirely new computer scientist/ systems engineering perspective on processing matter at the nanometre level. Indeed, I’ve recently started to collaborate closely with a colleague in Computer Science at Nottingham (on problems related to molecular computing) and find that we sometimes communicate in a language that is new for me but very similar to that used in “Nanosystems” (bootstrapping, “back chaining”,etc…). I note also that Don Eigler et al. have cited “Nanosystems” in their recent beautiful paper on molecular cascades [Science 298 1381 (Nov. 2002)] in relation to the ‘mechanical computing’ angle. [And if we're talking about 'forefathers' of nanotechnology, Eigler (alongside others such as Binnig and Rohrer, Kroto and Smalley, Cees Dekker, Whitesides ...etc...) is a much, much more appropriate choice than Drexler.]

      So, while I consider Drexler’s writings to offer an interesting, though-provoking perspective on nanoscience, not only did “Engines of Creation” etc… not inspire *me* to work in nanometre scale science, I would argue that Dr. Drexler’s work has been read by an extremely small fraction of the nanoscience community.

      “What does this have to do with Drexler?. Well, for one thing, Richard Smalley, the person who discovered the BuckminsterFullerene (the break through that led to the discovery of Carbon Nanotubes) has said that Engines of Creation is one of the things that inspired him to enter the field in the first place”.

      While I agree with you that Smalley has stated that “Engines of Creation” inspired him to enter the field of nanotechnology, you seem to be arguing here on the basis of the following chain of events:

      Drexler publishes “Engines of Creation” -> Smalley reads “Engines of Creation” (in 1991 – see http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html)and is inspired to enter field of nanotechnology -> Smalley, Kroto et al discover fullerenes.

      This is not how it happened! Kroto, Smalley et al. published their pioneering C60 paper in 1985 (i.e. 6 years before Smalley read “Engines of Creation”). There is no direct link between the discovery of buckminsterfullerene and Drexler’s work. Of the work on carbon nanotubes and fullerenes published to date of which I’m aware, there is no link to Drexler’s writings. How many fullerene and nanotube-related papers cite Drexler’s books or papers? I’d argue that it’s a number quite close to zero. If Drexler has been such an inspiration for fullerene and nanotube-related work (and indeed nanoscience in general), why aren’t his books cited time and time again in research papers?

      “Drexler took the principals that Feynman laid out and expanded them to explain what is humanly possible carrying this concept to ité─˘s extreme.”

      I think you may be interested in the debate that Chris Phoenix (at the Centre for Responsible Nanotechnology) and myself have pursued in recent weeks. That debate will be published here soon and at times focusses on issues such as you raise above. Similarly, you might want to read my comments on “Universal Assemblers” elsewhere in this blog [http://www.softmachines.org/wordpress/index.php?p=50).

      "....his vision of é─˙What a Nanotechnological era is?é─¨ is a much bigger contribution than any particular step thaté─˘s taken on the path to the positional control of matter that I mentioned at the begining of this post"

      Not if that vision isn't feasible because there are severe difficulties with the underlying chemistry. My problem with Drexler's work is indeed the "black box" problem you raise in your original post. What's the point in basing an entire technology around mechanosynthesis if the low level "machine language" steps have not been considered in sufficient detail with regard to their viability? Again, issues such as these have been discussed in my debate with Chris Phoenix - I'll try to get the debate documents to Richard (Jones) asap so he can post them on this blog site.

      "Ié─˘m not trying to minimize what scientists in the field do, but evaluating Drexler as a scientist is like evaluating Michael Jordané─˘s golf game."

      Drexler would (quite rightly) strongly baulk at the suggestion that he's not a scientist. Have a look at his CV (http://www.imm.org/DrexlerCV.html). In addition, he put a lot of time and effort into "Nanosystems" and, as both Richard and I have previously stated, there are no *obvious* flaws in the physics. (Although I *do* have key problems with some of the proposed mechanosynthetic mechanisms...again, these are discussed at length in my debate with Chris). Nevertheless, you seem to argue that it's OK to have a "vision" without backing that vision up with hard science. This is what I'd call science fiction. Drexler has argued time and time again that his work does not below in the realms of science fiction. [But can science fiction be inspirational? Definitely! Asimov, Arthur C Clarke, Douglas Adams, Iain Banks, William Gibson.... for me, the list is almost endless.]

      Best wishes,

      Philip

    13. Chris,

      “… the book é─˙Engines of Creationé─¨ and others by Drexler have inspired many people in the Nanotechnology field(s). While, it may not have inspired you, I do believe you are in the minority.”

      I think that you’d be very surprised at just how small a percentage of researchers currently working in nanometre scale science have *read* “Engines of Creation”, “Unbounding The Future”, or – in particular – “Nanosystems” let alone been inspired by Drexler’s writings. For example, I have spent quite a few days over the last month in a “Chemical Craftwork” workshop which involved a considerable number of scientists who work on nanoscale problems. Beyond the “grey goo” mythology, the vast majority of these scientists were not aware of Drexler’s work. Similarly, each of the postgraduate students who have worked (or currently work) in the Nottingham Nanoscience group have decided to take up a PhD not on the basis of Drexler’s work but because they were inspired by, for example and amongst a variety of possibilities, STM images of individual atoms, Eigler et al.’s atomic manipulation work, or results related to Kroto, Smalley et al.’s fullerene discoveries. [To date, ~ 30 students (including a considerable number of European students undertaking Marie Curie fellowships) have worked in the Nottingham group].

      Richard Jones and I are, I believe, in a rather small minority as physicists who have invested the time and effort to read “Nanosystems”. As, I’ve mentioned before, it’s an interesting book to read as, for me, it presents an entirely new computer scientist/ systems engineering perspective on processing matter at the nanometre level. Indeed, I’ve recently started to collaborate closely with a colleague in Computer Science at Nottingham (on problems related to molecular computing) and find that we sometimes communicate in a language that is new for me but very similar to that used in “Nanosystems” (bootstrapping, “back chaining”,etc…). I note also that Don Eigler et al. have cited “Nanosystems” in their recent beautiful paper on molecular cascades [Science 298 1381 (Nov. 2002)] in relation to the ‘mechanical computing’ angle. [And if we're talking about 'forefathers' of nanotechnology, Eigler (alongside others such as Binnig and Rohrer, Kroto and Smalley, Cees Dekker, Whitesides ...etc...) is a much, much more appropriate choice than Drexler.]

      So, while I consider Drexler’s writings to offer an interesting, though-provoking perspective on nanoscience, not only did “Engines of Creation” etc… not inspire *me* to work in nanometre scale science, I would argue that Dr. Drexler’s work has been read by an extremely small fraction of the nanoscience community.

      “What does this have to do with Drexler?. Well, for one thing, Richard Smalley, the person who discovered the BuckminsterFullerene (the break through that led to the discovery of Carbon Nanotubes) has said that Engines of Creation is one of the things that inspired him to enter the field in the first place”.

      While I agree with you that Smalley has stated that “Engines of Creation” inspired him to enter the field of nanotechnology, you seem to be arguing here on the basis of the following chain of events:

      Drexler publishes “Engines of Creation” -> Smalley reads “Engines of Creation” (in 1991 – see http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html)and is inspired to enter field of nanotechnology -> Smalley, Kroto et al discover fullerenes.

      This is not how it happened! Kroto, Smalley et al. published their pioneering C60 paper in 1985 (i.e. 6 years before Smalley read “Engines of Creation”). There is no direct link between the discovery of buckminsterfullerene and Drexler’s work. Of the work on carbon nanotubes and fullerenes published to date of which I’m aware, there is no link to Drexler’s writings. How many fullerene and nanotube-related papers cite Drexler’s books or papers? I’d argue that it’s a number quite close to zero. If Drexler has been such an inspiration for fullerene and nanotube-related work (and indeed nanoscience in general), why aren’t his books cited time and time again in research papers?

      “Drexler took the principals that Feynman laid out and expanded them to explain what is humanly possible carrying this concept to ité─˘s extreme.”

      I think you may be interested in the debate that Chris Phoenix (at the Centre for Responsible Nanotechnology) and myself have pursued in recent weeks. That debate will be published here soon and at times focusses on issues such as you raise above. Similarly, you might want to read my comments on “Universal Assemblers” elsewhere in this blog.

      “….his vision of é─˙What a Nanotechnological era is?é─¨ is a much bigger contribution than any particular step thaté─˘s taken on the path to the positional control of matter that I mentioned at the begining of this post”

      Not if that vision isn’t feasible because there are severe difficulties with the underlying chemistry. My problem with Drexler’s work is indeed the “black box” problem you raise in your original post. What’s the point in basing an entire technology around mechanosynthesis if the low level “machine language” steps have not been considered in sufficient detail with regard to their viability? Again, issues such as these have been discussed in my debate with Chris Phoenix – I’ll try to get the debate documents to Richard (Jones) asap so he can post them on this blog site.

      “Ié─˘m not trying to minimize what scientists in the field do, but evaluating Drexler as a scientist is like evaluating Michael Jordané─˘s golf game.”

      Drexler would (quite rightly) strongly baulk at the suggestion that he’s not a scientist. Have a look at his CV on the web. In addition, he put a lot of time and effort into “Nanosystems” and, as both Richard and I have previously stated, there are no *obvious* flaws in the physics. (Although I *do* have key problems with some of the proposed mechanosynthetic mechanisms…again, these are discussed at length in my debate with Chris). Nevertheless, you seem to argue that it’s OK to have a “vision” without backing that vision up with hard science. This is what I’d call science fiction. Drexler has argued time and time again that his work does not below in the realms of science fiction. [But can science fiction be inspirational? Definitely! Asimov, Arthur C Clarke, Douglas Adams, Iain Banks, William Gibson.... for me, the list is almost endless.]

      Best wishes,

      Philip

    14. Erratum to previous comment.

      “Drexler has argued time and time again that his work does not below in the realms of science fiction.”

      should of course be:

      “Drexler has argued time and time again that his work does not belong in the realms of science fiction.”

    15. Philip Moriarty says:

      Chris,

      Further to my comments above and, in fairness, I should note that Drexler’s work is cited frequently by biochemists and that, according to ISI Web of Knowledge statistics, “Nanosystems” has been cited a total of 318 times. (His original Proc. Nat. Ac. Sci. paper has been cited 128 times). This is quite a large number of “hits” and demonstrates that Drexler’s work in general has made a substantial impact. In my experience though, and certainly in terms of those working on atomic precision single molecule manipulation, “Nanosystems” has not inspired a large section of the community. Moreover, I hold firm to my view that it is misleading to suggest that advances such as single atom positioning and nanotube advances “stem” directly from Drexler’s work. Nevertheless, it is somewhat presumptuous for me, as a physicist, to attempt to gauge Drexler’s impact on other fields and it is likely that he deserves more credit (in areas such as protein design) than my comment above (#10) would suggest.

      Best wishes,

      Philip

    16. Philip Moriarty says:

      “Of the work on carbon nanotubes and fullerenes published to date of which Ié─˘m aware, there is no link to Drexleré─˘s writings.”

      This requires clarification as it’s very clumsily worded and thus misleading (…write in haste). There are indeed papers related to nanotubes and fullerenes which cite Drexler’s work. However, this is rather different from suggesting that Drexler’s writings inspired the entire field of nanotube and fullerene chemistry.

      Apologies.

      Philip

    17. Richard Jones says:

      Chris Gilliard raises an interesting point. My own perspective on this is that we should distinguish between the Drexler of Engines of Creation and the Drexler of Nanosystems. Engines Drexler made a visionary statement about what nanotechnology might lead to, without being too specific about the details of how it would be done. This was important and influential. Then Nanosystems Drexler devised a specific route by which he proposed to reach the general goal. Although I’m sure that many things won’t turn out the way he suggested in Engines of Creation, I quite agree with you that that’s not the point and we shouldn’t evaluate this on purely scientific grounds. But the specific proposal for nanotechnology described in Nanosystems very definitely is a scientific proposal and should be judged on that basis.

    18. Chris Gilliard says:

      Ok, sorry for not responding lately. I’ve been a little bit busy. I guess the main point I’m trying to make about Drexler is the following: As an electrical engineering student I was fascinated by the fact that there are so many levels of technology that make up a computer. You can look at a computer at the Device Physics level, the transistor level, the gate level, the Integrated circuit level, the machine language level, the compiler level, and the high level programing level. You can compare this to nanotechnology in many ways. Most of today’s research is being done on the equivilent of the Device Physics level or maybe the transistor level. Drexler’s work was mostly on the high level programming level in this analogy. The thing that is unique to this situation is that Drexler developed many of these ideas before we had even invented the transistor level technology that is required to complete his vision. Although he had a good idea that a lot of the lower level technologies were possible, he did not really set out to solve every problem in the field. That’s the job of the scientific community. In fact, asking Drexler to come up with all the answers would be the equivelent to asking a programmer working on the protein folding problem to come up with the solution at the transistor level as opposed to using a high level programming language. While every level of technology is important to the whole picture, my point is that Drexler’s work on the highest (the high level programming language equivelent level) level is not something to be scoffed at. Also, my other point is to not take an exclusively scientific look at Drexler’s work. There are many factors that contribute to technological progress. Vision is also important and that’s where my “Michael Jordan’s golf game comment” came from. Also, one other point I want to make. I think there’s a misconception that nanoscale science and engineering is made up of an elite small group of researchers at a few dozen universities and research facilities. I don’t agree with that point of view. Anyone working biotechnology, ic design, material science (for some materials), and others either are or will be dealing with nanoscale issues in the future. Also, programmers and system designers will be another important component to the equation when all is said and done because once we have the capabilities to easily make things like nanotubes in locations we want them, the challenge then becomes, what do we tell them to form and how do we program them.

    19. Philip Moriarty says:

      Hi Chris,

      Richard makes some important points pertinent to our comments above (and which have arisen during my debate with Chris Phoenix) at: http://www.softmachines.org/wordpress/index.php?p=71. In particular, he states: “… the nature of these elementary operations cané─˘t always be divorced from the higher level architecture. A good example comes from the operation of genetics, where the details of the interaction between DNA, RNA and proteins means that the distinction between hardware and software that we are used to cané─˘t be sustained.”

      I am in complete agreement with this – a keen difficulty I have with the Drexlerian strategy is that advanced physics and chemistry are apparently seen as secondary issues with respect to the systems engineering. Moreover, Richard’s post highlights the importance of letting the science and the results of experiments dictate the direction of the technology. This is counter to the Drexlerian stance where ‘engineering around’ issues of physics, chemistry, and materials science is paramount. The problem is that the physics, chemistry, and materials science issues crop up at every level of abstraction and continually narrow the viable parameter space (in terms of choice of materials, tip shapes, etc…).

      You note in the preceding comment: “The thing that is unique to this situation is that Drexler developed many of these ideas before we had even invented the transistor level technology that is required to complete his vision.” In response to this, I’ll cite a comment by Eric Kidd in a post elsewhere on this site: “Drexleré─˘s work in Nanosystems rests on the assumption that feasible mechanosynthesis operations exist for stiff hydrocarbons. If such pathways cané─˘t be found, Nanosystems collapses like a house of cards.”

      You also note: “I think thereé─˘s a misconception that nanoscale science and engineering is made up of an elite small group of researchers at a few dozen universities and research facilities. I doné─˘t agree with that point of view.”

      We need to distinguish between the Drexlerian ‘radical’ molecular nanotechnology vision (as outlined in “Nanosystems” and expounded by, for example, the Center for Responsible Nanotechnology) and other forms of nanotechnology/ nanoscience. There are vast amounts of money being poured into nanoscience across the world (e.g. “Federal funding for nanotechnology R&D has increased sixfold, from $116 million in 1997 to an estimated $961 million in 2004″, http://www.nano.gov/html/facts/faqs.html) and there are many hundreds/thousands of groups working on non-Drexlerian nanotechnology. On the other hand, there is currently *no* experimental effort towards the implementation of Drexlerian nanotechnology (molecular manufacturing) and the community in that case largely comprises a small number of computational chemistry/ computer science groups.

      Best wishes,

      Philip