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Home > The Atkinson-Phoenix Nanotech Debate -- Page 2

The Atkinson-Phoenix Nanotech Debate - Page 2 - Emails

Commentary text by Chris Phoenix, except where otherwise noted. [Bracked Italics] indicates a correction. Italics used on text indicates a comment taken from an earlier email, written by the other person.

Last update: August 04, 2003.

Page 1: Overview
Page 2: Emails through June 27, 2003
Page 3: Emails through July 14
Page 4: Emails through August 4
Page 5: The wrap-up

June 17, from Bill Atkinson to Rocky Rawstern (editor of Nanotech-Now, which published my review)

Dear Mr Phoenix: A brief response to the on-line review of Nanocosm.

Most of the review's objections can be put to rest by my interviewees. Anatomical and functional distinctions between grey and white brain tissue are those of Roger Fouts of The Chimpanzee and Human Communication Institute, Central Washington University; laser spectroscopist Geraldine Kenney-Wallace has documented how chemical reactions commonly occur in a few tens of femtoseconds; etc.

Of course conventional thermodynamic calculations forbid a Maxwell demon; my suggestion is tongue-in-cheek. Yet consider that if CERN characterizes the Higgs boson by 2005, resultant innovations such as synthetic gravity might also violate current theory. New data invariably encapsulate old theory as a special case.

I fully defend all observations and conclusions about Eric Drexler. Science demands skepticism about anything imagined yet unproduced. One could argue details forever, but two facts seem incontrovertible. First: If all objections are answered, where is the device? If A then B: Not-A: Therefore not-B. Second: Mr Drexler himself is on record that nanotechnology has been empirically redefined, and must now be considered separate from the molecular assembler (New Scientist, 2003 April).

From molecular switches to metallic ceramics and fullerene structures, from parallel failure-tolerant nanoarchitectronics to the renascence of analogue, real nanoscience is rapidly producing tangible, bankable results. Mixing up such genuine work with unproven speculation, no matter how fascinating, does no one any service.

Sincerely

William Illsey Atkinson, June 17th, 2003


June 17, from Bill Atkinson to Chris Phoenix
Subject: Review Response

Hi Chris: Don't know if you've seen this [response above]; I sent it this A.M. to Rocky Rawstern. We probably have to agree to disagree, but hey - worse feuds have ended in a surprising acreage of common ground.

Best regards

Bill


June 17, from Chris Phoenix to Bill Atkinson
Subject: Re: Review Response

Rocky forwarded it to me. That's why I sent the email to Roger Fouts.

[I emailed Roger to find out if he really said what Bill reported about white matter. He really did; he was using "white matter" to refer to myelinated neurons--the whole neuron, including the gray cell body, not just the part with the myelin. I have not heard this usage elsewhere, and my bio textbook contradicts it. So I think Bill and I are both right on this one. --CJP]

I'll probably put a footnote in the review on the gray/white matter thing. I'm still deciding what it'll say--probably something to the effect that your statement was a plausible reading of what Fouts wrote, but what Fouts meant was (etc).

However, this doesn't affect my other statements about the technical inaccuracies in the book, and I stand by my statement that there are too many of them to recommend the book. I didn't cover all of them in the review. Your discussion of the buckytube golf club gives a very wrong impression of the properties of buckytubes (and the physics of things moving through air, and what it takes to move a golf ball, etc.) There are many engineering details wrong in your description of the space tower. Your design for the diamond-making cellular automaton--"Make all carbon bonds covalent"--is unworkable and based on a false assumption (carbon bonds are already covalent). I could go on for a long time.

Your "Maxwell Demon" suggestion might be excused as tongue in cheek on page 79, but not on page 277. To defend that, you might have to say something like, "resultant innovations such as synthetic gravity might also violate current theory. New data invariably encapsulate old theory as a special case." This may be true, but I might reply, "Mixing up ... genuine work with unproven speculation, no matter how fascinating, does no one any service."

I fully defend all observations and conclusions about Eric Drexler. Science demands skepticism about anything imagined yet unproduced.

Science demands skepticism, yes, but not ridicule. Science demands testing of hypotheses, not insulting rhymes. And in fact, your objections against nanobots are also unproven speculation. You don't actually know whether assemblers can maintain their internal state with sufficient precision; to state categorically that they can't is far less justified than claims that some assembler designs probably can.

One could argue details forever, but two facts seem incontrovertible. First: If all objections are answered, where is the device?

This is a question, not a fact, and it has a simple answer. Answering the objections doesn't build the device. No one pretends that it will be simple, or could be done in a year by grad students. Since absence of the device is easy to explain, it provides no evidence for its impossibility.

To be scrupulously fair, the last objection won't be answered until the device is actually built. But the question at this point is not whether every single objection is answered to the satisfaction of the objector, but whether there are any showstoppers in the laws of physics, the design capability of computer-aided humans, or the realities of economics or politics. There are no known showstoppers. You think you've found a whole new crowd, like the claim that carbon is death to a nanomachine, but this is just because your understanding is superficial. You have also found some difficulties, such as the storage required to specify a nanobot being larger than the bot itself. This is not a showstopper, and perhaps one of your biggest mistakes is treating every difficulty as a showstopper. With enough work, difficulties can be overcome, and we already know how to solve every one you mention in your book.

If A then B: Not-A: Therefore not-B.

The correct version is "If A then B: Not-B: Therefore not-A." The version you gave is invalid. For example, if it's a horse, then it's a quadruped. It's not a horse (it's a pig): therefore it's not a quadruped. I harp on this because it demonstrates either carelessness or lack of knowledge--which is also present throughout the book. Someone who is expert in a field can afford to be self-assured. But you cannot afford to believe things just because they seem sensible to you. Many of your concerns about Drexler's work are quite easy to answer. Many others are simply wrong, such as your claim that he thinks nanoscale engineering is "same old stuff"--chapter 2 of Nanosystems disproves that.

Second: Mr Drexler himself is on record that nanotechnology has been empirically redefined, and must now be considered separate from the molecular assembler (New Scientist, 2003 April).

I don't see what this has to do with the technical feasibility of Drexler's proposals.

It does have significance for investors: since there are two fields labeled "nanotechnology", they need to know the difference before they can decide what they want to invest in. Drexler has done his best to clarify the difference, by inventing a new term for his work: "molecular nanotechnology." The confusion is certainly not his fault, and he is not trying to exploit it--quite the opposite. A book that made clear the difference between today's nanoscale technology and Drexler's projections of molecular manufacturing would have been quite appropriate and useful. But you chose to emphasize the difference through ridicule, unfounded technical criticism, and personal attack. That was unnecessary. And unfair to your readers. And, I think, led you into intellectual dishonesty, such as complaining about Drexler's supposed lack of provision for cooling immediately after complaining about his analysis of cooling systems.

We could spend many hours discussing the specific areas where your understanding is lacking and Drexler's work does not deserve the criticisms you have leveled against it, but I suspect in the end, this would do nothing to change your opinion of Drexler's results. It is easy for me to see where you are wrong, but it will be a lot harder for you to see where you're wrong. But if you're not willing to go there, I don't know that we can find any common ground.

Some of your criticisms are worth answering. I have been working on a paper that addresses issues of control and integration: Assuming we can build a single assembler, how can it be integrated/bootstrapped into a tabletop nanofactory capable of building products from a CAD file? The paper is over 50 pages, and not done yet. It is not a simple problem to solve. But I have not run across anything that stumped me, and I've considered control, power, chemical distribution, heat dissipation, component failure, assembly robotics, and several other issues. I believe I've solved each of these in enough detail to show that a usable design for the entire factory could be completed today.

There are two possible responses to this. One is to say, "Well, maybe I was wrong about how impossible it will be to control trillions of assemblers. Can I see the paper so I can check your assumptions?" The other response is to say, "Yes, but assemblers are impossible, so what you're doing is stupid." I could answer by defending the idea of assemblers, but that's just playing whack-a-mole and will waste both our time. So if that's the response I got, I'd answer that we can't find common ground after all.

Chris


June 17, from Bill Atkinson to Chris Phoenix
Subject: Re: Review Response

Hi Chris,

Me culpa on the Modus tolens; that was a typo. So was p.277, in a list the publisher prepared, and whose error I missed in proofing. I'll correct it in the second edition. Thanks too for offering to post a clarification on the Fouts thing: it speaks well for your intellectual honesty. Still, "what Fouts really meant" seems a grudging allowance, and misleading at that. What Roger meant is precisely what I say he meant - that white matter (rich in neurons with myelinated axons) may well have different cerebral processing functions than grey matter (poor in such neurons). You may catch me in other places, but this isn't one of 'em.

The golf club is another jeu d'esprit, which I thought would give the technically minded a smile. Joe III has considered the equation K = 1/2MV.V (sorry, can't get a superscript with this E-mail program). Joe has seen, correctly, that doubling mass doubles kinetic energy, while doubling velocity quadruples it. But he's concluded, probably incorrectly, that an ultra-light golf club moving at a higher velocity would impart greater specific impetus than a heavier club moving more slowly. This approach has also been adopted by the Army in its assault rifles: much lighter bullet, much higher velocity. As Joe says, sniffing a rat, the new club must be tested. I wanted to convey some of the uncertainty that accompanies all technical development, plus the chance once always takes of being off base when attempting something radically new.

In the larger issue of whether a nanoassembler is possible, I have to say you're making inroads on me. When I studied anthropology, one of the concepts that interested me was acculturation - the fireworks and synthesis that happen when two world-views collide. If I'm wrong I'll admit it; I'm willing to learn. About covalency, for example: I worked from the datum that every other bond in the benzene ring, not every single bond, is shown with the double line.

Beyond the details, however, there are issues here that you've shrugged off too easily in your quest for a nanoassembler, and other issues that you haven't addressed at all. Among the former: Rick Smalley. The guy's a beacon of science, a Nobel laureate, an incredible experimentalist and theoretician: one who's helped pioneer our knowledge of the nanocosm. I've read the IMM and open-letter responses and conclude that Rick's arguments, based as they are on extensive knowledge and genuine observation rather than what-we-think-should-be-in-there, have in no way been dismissed. In fact I get a strong sense that the open letter was really addressed to the faithful: Don't lose heart, we're going to do this, Smalley doesn't know what he's talking about.

I also retain deep misgivings about Drexler's approach. When I read the New Scientist interview, I thought: We agree! If he'd said that a year ago, and showed he believed it, I wouldn't have been hard on him. In fact I never started out to slag the guy. But the more I compared his legitimacy ratio [i.e. public mindshare divided by scientific achievements] with those of real nanoscientists, the more annoyed I got. Moreover, the websites with which Drexler is affiliated continue to mix up new experimental data with what SciAm calls his "quaint notions." Evidently Drexler continues his game plan of legitimacy-by-association, appropriating the results of genuine R&D as if they supported his ideas. It is exactly this obfuscation that I wanted to spotlight.

I still say, with Smalley, that the burden of proof is on you guys to show this thing is possible. Not calculate it, not print equations on paper, but demonstrate it. My God, Chris, think what you're trying to do! This makes the Industrial and Cybernetic Revolutions look like walks in the park. A self-directing, self-replicating assembler hasn't been achieved on a one-meter scale. Trying to jump six or seven orders of magnitude down the pipe defies understanding. I boggle, I truly do.

As for your answer - "Stay tuned, we're working on it" - I also address this rhetoric in the book. Saying something will happen can never be disproven; saying something won't can be disproven at any instant. In debating terms, I'm the guy who's out on a limb. But I'm confident no one's going to saw it off. So prove me wrong.

And, hell, you may! I grind my teeth to say it, but you have managed to do something I'd thought was impossible: make me reconsider my position that the nanoassembler cannot be achieved in principle. I do remind you, however, that it may well be impossible in fact. In either case, i.e. in both scientific theory and engineering practice, the burden of proof remains wholly on you.

Another point your review ignored: Even if the nanobot is possible, why bother? Why break our brains developing something as incredibly fiddly, complex, unproven, and improbable as a nanoassembler when self-assembly has proven itself a highly flexible success for three billion years? I have to wonder if, psychologically, the nanobot isn't simply the unnecessary, hubristic self-projection of the engineer into the nanocosm - "I'm here, and here to dominate."

The day anyone demonstrates a working nanorobot in sequential AFM images, one with onboard software storage, with interior or even exterior power source and heat management, I will take out an ad in the New York Times publicly declaring I was absolutely wrong, and offering a grovelling apology to Mr Drexler, the Foresight Institute, the IMM, yourself, and your whole community. So do it: prove I'm mistaken.

I don't think you will. Answered every argument, overcome every objection? You haven't done enough genuine science to start listing your real problems - neither experiments to find how the nanocosm really behaves, nor practical engineering. Calculation might be necessary to make a nanoassembler, but it is hardly sufficient. Every dollar spent on a technical will-o'-the-wisp like the nanoassembler still seems to me to be a dollar taken from legitimate nanoscience.

B.


June 18, from Chris Phoenix to Bill Atkinson
Subject: Intro and loose ends Re: Review Response

You have convinced me that you're willing to listen. In that case, I'm very willing to talk--and to listen as well. Perhaps we can find common ground after all.

This was getting really long, so after I wrote the answer, I broke it up into threads of personalities and motivations, feasibility and desirability, credibility of objections. Leftover stuff is below, including some science facts.

What Roger meant is precisely what I say he meant - that white matter (rich in neurons with myelinated axons) may well have different cerebral processing functions than grey matter (poor in such neurons). You may catch me in other places, but this isn't one of 'em.

More precisely, white matter is rich in the myelinated axons of neurons. The cell bodies are all in the gray matter. White matter alone can't process anything, any more than power lines can generate power or phone lines can generate signals. But I'm not trying to catch you on this one anymore--Fouts' statement was pretty confusing.

The golf club is another jeu d'esprit, which I thought would give the technically minded a smile.

I think it'd give the technically minded a knowing smirk, and confuse the others. It's not trivial to realize that people can't swing their arms fast enough to make a super-light golf club work. But the idea that a single buckytube could make a golf club shaft is worse: harder to know it's wrong, and more directly nanotech-related.

In the larger issue of whether a nanoassembler is possible, I have to say you're making inroads on me.

Cool. And, though I know a lot about technology and science, I don't know as much about economics and markets and user acceptance. You haven't made inroads on me yet, but you could, especially in those areas--though we might have to consider a variety of scenarios of MNT difficulty without agreeing on which was most accurate.

When I studied anthropology, one of the concepts that interested me was acculturation - the fireworks and synthesis that happen when two world-views collide.

Yep. As long as the two sides are willing to interact meaningfully. I'm not sure there's much synthesis coming out of the abortion issue. But I think we can maybe synthesize something useful.

About covalency, for example: I worked from the datum that every other bond in the benzene ring, not every single bond, is shown with the double line.

The difference between single line and double line is not about covalency. Both bonds are covalent. One is a single bond, and the other is a double bond (which is stronger, and involves twice as many electrons). Carbon wants to form four covalent bonds. In diamond and in many organic chemicals, this is four single bonds. In carbon dioxide, it's two double bonds. In graphite, it forms three covalent bonds, and the extra bond kinda' floats. And in benzene, the double bonds kinda' float around the ring; that's why it's sometimes drawn with a ring of single bonds and a circle inside. But AFAIK, carbon doesn't form any non-covalent bond.

Non-covalent bonds include ionic bonds (like in salt crystals) where instead of two electrons being shared between the atoms, one electron moves to the neighboring atom and the atoms are held together by electrostatic forces. Of course this is only an approximate description. And there are various other weaker kinds of interatomic bonds/forces: hydrogen bonds, sulfur bonds...

Diamond contains *only* carbon. To convert a tree into diamond, you'd have to break the covalent bonds between carbon and hydrogen, carbon and oxygen, etc that occur in the tree's chemicals; and make the carbon bond only to other carbons; and impose the regularity of the diamond lattice. This would not be easy--in fact, it would be somewhat harder than what nanobot assemblers are supposed to do.

Calculation might be necessary to make a nanoassembler, but it is hardly sufficient. Every dollar spent on a technical will-o'-the-wisp like the nanoassembler still seems to me to be a dollar taken from legitimate nanoscience.

Before we continue this particular thread, we should probably talk more about the likelihood that a nanoassembler can be built, and the probable utility if one is.

Chris


June 18, from Chris Phoenix to Bill Atkinson
Subject: Dealing with objections Re: Review Response

Beyond the details, however, there are issues here that you've shrugged off too easily in your quest for a nanoassembler, and other issues that you haven't addressed at all. Among the former: Rick Smalley. The guy's a beacon of science, a Nobel laureate, an incredible experimentalist and theoretician: one who's helped pioneer our knowledge of the nanocosm.

The nanocosm is huge, and Smalley is very good at exploring a tiny corner of it. If he expressed an opinion about biocompatibility of dendrimer drugs, no one would listen very hard--it's nanotech, but it's not his field. And although bucky structures and diamondoid are both made of carbon, nanobots aren't his field either. Much of his knowledge and observation doesn't apply. That's why I'm comfortable evaluating his arguments for myself on their own merits, without paying much attention to his reputation. He hasn't given nearly as much scientific attention to diamondoid mechanosynthesis and nanoscale engineering as Drexler has. But he's very smart and an excellent researcher; if he claims to have found problems with Drexler's theories, I'll listen. I'll even listen to his intuitions and projections. But since he's applying them in areas he hasn't directly studied, they're at least as questionable as Drexler's choices of equations and constants.

But some of Smalley's arguments are flat wrong. He talks about fingers gripping atoms. This has never been proposed, and he should know that. This particular argument is no more than a strawman. I wouldn't expect most people to realize this, but there's no question about it. To dismiss this argument does not require dismissing Smalley's technical knowledge--only disavowing the use of fingers to grip atoms, which doesn't hurt Drexler's case since he never suggested it.

For a while, Smalley was saying that chemistry requires dozens of atoms moving in intricate trajectories in a small space. That was wrong, and in his field too: burning hydrogen involves chemistry, but only a few atoms at a time. That makes it easy to dismiss him--perhaps too easy.

I have not seen more technical arguments from him. I don't know what work he has done to back up his popular pronouncements. But the pronouncements themselves do not convince me that he's even thought about it very much. And if he hasn't given it at least a little deep thought, then Nobelist or not, I'm not very worried about his pronouncement that it's impossible.

I've read the IMM and open-letter responses and conclude that Rick's arguments, based as they are on extensive knowledge and genuine observation rather than what-we-think-should-be-in-there, have in no way been dismissed.

The arguments about the number of degrees of freedom required are worth listening to. But here, Drexler has a strong case, and Smalley has damaged his credibility a little by his earlier "dozens of atoms" argument. Drexler described several structures in Nanosystems for holding reactive atoms stiffly a small distance away from a surface. If Smalley did some work to demonstrate that such structures wouldn't work as claimed, I'd pay very close attention, and I'd worry more than a little. But so far, Smalley hasn't seen fit to spend nearly enough time to criticize Drexler's work in detail.

And meanwhile, we've had at least two very different examples of covalent chemistry done by scanning probe microscope. In one, carbon monoxide was attached to iron. In the other, a single atom of silicon was plucked from a covalent silicon surface and then replaced in the same spot. Sure, it was a surface that's especially easy to work with. But if I understand Smalley's arguments, they would've said such a feat was flat-out impossible. Now that mechanochemistry on tetrahedral covalent lattices has been demonstrated, I think Smalley needs to decide how far to narrow his arguments.

I still say, with Smalley, that the burden of proof is on you guys to show this thing is possible. Not calculate it, not print equations on paper, but demonstrate it.

We're getting there. Pieces of it have already been demonstrated. I agree we won't know for absolute certain sure until it's demonstrated. But we can start talking now about possibilities, and to some extent even probabilities and capabilities.

Some of the big problems can legitimately be solved on paper. For example, assembler control: don't mount the computer, communicate from outside--and the fact that there are several ways to communicate under consideration makes it more likely to work, not less. Pressure pulses are so simple it's hard to imagine them not working.

I do think it's significant that Nanosystems is chock-full of testable hypotheses, and not one of them has been disproved yet. It's not just a big book full of equations; it's a big reliable book full of equations that, as far as we can tell, have been applied correctly.

In either case, i.e. in both scientific theory and engineering practice, the burden of proof remains wholly on you.

I disagree that the burden of proof is wholly on us in the area of scientific theory. When Engines of Creation came out, the stuff was largely unproven, and much of it was fantastic. But Nanosystems appears to establish quite a lot of scientific theory pointing directly at nanobots. It doesn't seem fair to expect us to do even more work before being willing to scientifically criticize any of it.

The day anyone demonstrates a working nanorobot in sequential AFM images, one with onboard software storage, with interior or even exterior power source and heat management, I will take out an ad in the New York Times publicly declaring I was absolutely wrong, and offering a grovelling apology to Mr Drexler, the Foresight Institute, the IMM, yourself, and your whole community. So do it: prove I'm mistaken.

What do you think of the Feynman Grand Prize? It's a somewhat simpler set of criteria, but it's well on the way to what you describe.

Keep in mind that the need for heat management depends on device size. A single nanobot can be cooled by conduction and requires no explicit heat management. A solid cubic meter of Drexler's nanocomputers couldn't be cooled by any means.

I don't think you will. Answered every argument, overcome every objection?

Answered every known showstopper, and a fair number of the practical problems.

You haven't done enough genuine science to start listing your real problems - neither experiments to find how the nanocosm really behaves, nor practical engineering.

We certainly have started listing the real problems. Heat, power, stiffness, control, design, and some chemistry. We also know quite a lot about how the nanocosm behaves. We certainly don't know enough yet that we could train a mechanical engineer to design nanobots. But I feel pretty comfortable in saying that nanobot design will turn out to be accessible to engineers. Remember, all we need is one assembler design plus a few modular functional designs to turn out a whole flood of products--and the product designer won't even have to know much chemistry.

(Discussion continues in "Feasibility.")

Chris


June 18, from Chris Phoenix to Bill Atkinson
Subject: Feasibility and desirability Re: Review Response

My God, Chris, think what you're trying to do! This makes the Industrial and Cybernetic Revolutions look like walks in the park. A self-directing, self-replicating assembler hasn't been achieved on a one-meter scale. Trying to jump six or seven orders of magnitude down the pipe defies understanding. I boggle, I truly do.

And the Industrial and Cybernetic revolutions aren't even over yet. Their logical end point--which we're steadily moving toward--is a convergence of rapid prototyping and automated assembly, with extreme levels of miniaturization. Hm... sounds familiar. I think that even if we never worked directly on MNT, we'd get there around 2030 or 2050 anyway.

The reason for trying to do manufacturing at a smaller scale is that some things get a lot easier at that scale. At the human scale, it takes millions of different kinds of operations to make a general-purpose factory. But if you're working directly with chemistry, it may take only a few hundred operations, repeated millions of times. Computers take advantage of this; a single logical operation, NOR (or NAND), is enough to build an entire computer capable of editing your home movies.

Yes, some things are harder at the nano scale. We're not used to working there. And it has to be kept very clean and orderly. And bootstrapping will be a pain and a half. But the practical advantages make it look worthwhile. Bearings with no static friction--this may sound incredible, but it's not: in fact, mainstream buckytube researchers have reported it already (though I suspect they were overeager to see it). Motors with incredible power densities. (Electrostatics are inherently efficient, and work better at small scales--MEMS already use them.) Super-strong materials.

But the biggest draw of molecular manufacturing is the ability to build a wide variety of parts, with a wide variety of properties, and incredible precision, using only a few operations in programmable sequence. This is why we think we can get self-rep at the nanoscale before the human scale.

As for your answer - "Stay tuned, we're working on it" - I also address this rhetoric in the book. Saying something will happen can never be disproven; saying something won't can be disproven at any instant. In debating terms, I'm the guy who's out on a limb. But I'm confident no one's going to saw it off. So prove me wrong.

Give us a decade. :-) This one, we'll have to wait and see on. But on issues of whether it's worth doing (assuming it can be done), I think I can give you a strong argument today.

And, hell, you may! I grind my teeth to say it, but you have managed to do something I'd thought was impossible: make me reconsider my position that the nanoassembler cannot be achieved in principle. I do remind you, however, that it may well be impossible in fact.

We know that protein nanoassemblers are possible. But they're hard to work with, and produce only so-so materials. If I knew all we'd ever have was protein, I'd probably fold CRN and work on dyslexia or AI. Are diamondoid nanoassemblers impossible? We can't know for sure. There are no known showstoppers. There's suspicion from Smalley, an excellent chemist, that mechanochemistry may have too many practical limitations. There's partial evidence from Drexler that we can probably do at least some diamondoid. There are lots of unsolved questions. Many of them will take hard work, but it's pretty certain that we can find solutions. Some of them may turn into showstoppers. My own experience, both as an embedded software engineer and as a nanotech theoretician, tells me that there probably won't be showstoppers. There may be crippling costs: at energy costs of $1000/kg (calculated by Merkle for a very primitive assembler design), not many products would be worth building. But even at that point, it'd be worth building weapons, so we'd have to start considering policy. And Merkle's design can probably be made more efficient by two orders of magnitude once it's integrated into a nanofactory. Just replace the ratchets with a reversible logic drive.

Another point your review ignored: Even if the nanobot is possible, why bother? Why break our brains developing something as incredibly fiddly, complex, unproven, and improbable as a nanoassembler when self-assembly has proven itself a highly flexible success for three billion years?

The exact same things are true of digital computers and their software. Fiddly, complex, and improbable. A bit (logical 1 or 0) is a good candidate for the most unnatural thing in the universe. A computer does trillions of bit operations every second, with negligible error. And why? So that I can move my mouse around the screen and fix typos without having to retype the whole page. Or look up a phone number without having to leaf through a Rolodex. Or just play Minesweeper.

But computers are still useful. Improbable: handling bits. But that lets them deal with any kind of information: movies, weather simulations, databases. Likewise, a programmable assembler should let us build a wide variety of products without retooling and retraining.

Complex: A computer has about twelve levels of abstraction from the silicon to the GUI. We throw away most of its potential power, just so we can think about fields instead of variables; variables instead of registers; registers instead of transistors. We throw away more power by ignoring analog logic values. Likewise, usable MNT will require intense simplification at every step, and most of its potential power will be inaccessible. But what's left over will, I think, still be revolutionary.

Fiddly: Like I said, computers do quintillions of operations per hardware error (software errors are usually more frequent). This is possible because bits have built-in error correction--the flip side of throwing away the analog. Likewise, diamondoid mechanochemistry is hard-edged on purpose: by using only stiff machines to build only stiff things, we expect to get ridiculously small error rates--enough to remove a lot of the fiddle. Biochemistry includes about one error in every ribosome. Test tube chemistry copes with fractional yields at each step. These processes produce lots of error, and must deal with it. But mechanochemistry offers the chance to overdesign right at the beginning, so that we don't have to worry about errors until we get up to the micron scale. If the theory holds, this will open a new and potentially very useful design paradigm.

You haven't done enough genuine science to start listing your real problems - neither experiments to find how the nanocosm really behaves, nor practical engineering.

[I was wrong: the books aren't Zyvex projects; they're private projects of Freitas and Merkle. And the schedule on Diamond Surfaces had slipped since the last time I looked. See http://rfreitas.com/#Replicators --CJP]

Zyvex is coming out with a book, hopefully later this year, on diamondoid surface chemistry. There's another one on assembler requirements. Freitas, one of the authors on both of them, is an extremely careful and thorough worker. (The other author is Merkle, and we'll probably disagree on his reliability. But Freitas wouldn't let anything be published with his name on it unless it was absolutely solid.) I don't know what's in the books, but I'm eagerly looking forward to them.

There are sub-problems we haven't looked at much yet. Aside from one section in Nanosystems and one paper by Merkle, I haven't seen much discussion of how to make "binding pockets" for sorting or organizing molecules from solution. (Freitas discusses this in Nanomedicine, but he's assuming a more advanced nanotechnology.) In theory, there might be a showstopper here. And although there's been some work on mechanochemical tools and reactions, we need a lot more.

But in many areas, we've made great progress at breaking down problems into subproblems that we should be able to handle. I'm now confident that given an assembler we can make a working and useful nanofactory--there are no showstoppers left. And my impression, based on non-detailed conversations with them, is that Freitas and Merkle have reached a similar stage on the assembler design. [When I double-checked, Freitas expressed discomfort with a blanket "no showstoppers" claim. --CJP] And if we have a robot capable of doing general mechanochemistry, programming that robot will not be too difficult. To me, the biggest question is about funding, and the second biggest is about sensing--the job will be much easier if we can actually look at what we're doing as we do it. There's a company called AngstroVision that claims to have developed a sub-wavelength non-proximal 3D optical sensing technology that'll go down to voxels of a few nanometers. They're still in stealth mode, but if they're right, we'll be able to debug our designs a lot more quickly.

Chris


June 18, from Chris Phoenix to Bill Atkinson
Subject: Personalities and Motivations Re: Review Response:

In fact I get a strong sense that the open letter was really addressed to the faithful: Don't lose heart, we're going to do this, Smalley doesn't know what he's talking about.

I've known Drexler for years, and I've talked with him about the letter. He meant it to be a serious challenge to Smalley: quit criticizing strawmen and address the actual proposals. I do not believe he was grandstanding at all. He copied the letter to some futurists and journalists of course, but most of the list was scientists, government people (at least one senator), academics, science magazines...

I also retain deep misgivings about Drexler's approach. When I read the New Scientist interview, I thought: We agree! If he'd said that a year ago, and showed he believed it, I wouldn't have been hard on him.

Hm. What he said in the interview is cautious, but there's nothing in there that backs off from Nanosystems. It looks to me like both he and the interviewer were focusing mainly on the near-term stuff, and not talking about diamondoid at all. But he says: "Doing studies of molecular manufacturing at this point is like studying space flight before Sputnik or studying fission chain reactions before the Manhattan Project. But in all these cases you use standard applied physics methods to study the consequences of known phenomena." He clearly still believes that molecular manufacturing will be possible and significant, and that we can already study some aspects of it.

In fact I never started out to slag the guy. But the more I compared his legitimacy ratio [i.e. public mindshare divided by scientific achievements] with those of real nanoscientists, the more annoyed I got.

Most nanoscientists aren't working to gain public mindshare. Drexler has for decades been concerned about the policy implications of MNT, and in the mid-eighties decided to go public with his concerns. This was not a scientific thing to do, and if judged in a scientific context, it is certainly annoying. But it doesn't mean the science he's done is invalid. It also doesn't mean his science is any more valid, just because more people pay attention to it. In fact, it has no bearing on the validity of the science.

Drexler's going public is a lot less self-serving than some of the other scientists who have done so. For example, there's a group of dyslexia researchers who have developed and commercialized an auditory-based method of treating dyslexia. They have gone public with the claim that dyslexia has nothing to do with vision--which is demonstrably incorrect. But they get lots of news stories and lots of publicity for their method.

Drexler didn't do it to get funding, or money, or even fame. He did it to get people talking about the policy implications of MNT. If I were a nanotube or dendrimer or quantum dot researcher, I might be annoyed and envious at his publicity. But as a member of the public, I'm glad he did it. It might have been better if he'd found someone else to do the publicity side. But I'm not sure anyone but a researcher would have had the credibility at that early stage.

Moreover, the websites with which Drexler is affiliated continue to mix up new experimental data with what SciAm calls his "quaint notions." Evidently Drexler continues his game plan of legitimacy-by-association, appropriating the results of genuine R&D as if they supported his ideas. It is exactly this obfuscation that I wanted to spotlight.

The legitimate research is supporting more and more of his technical claims. Since many of his claims have been attacked in the past, I don't blame him for pointing out when the research contradicts some old (or not-so-old) criticism.

There's a subtle point here. The external research supports the technical claims. He reasons from the technical claims, to product claims, to policy claims. The external research does not (yet) directly support product or policy claims, and he doesn't say that it does. But the policy issues are important, and he feels he has to talk about them. And to defend the technical claims that the policy issues are based on, he has to talk about external research. Maybe he could make it clearer--but he'd be misread no matter what he did. I don't think he's deliberately trying to obfuscate.

I have to wonder if, psychologically, the nanobot isn't simply the unnecessary, hubristic self-projection of the engineer into the nanocosm - "I'm here, and here to dominate."

Close. The nanobot is certainly a projection of engineering into the nanocosm. As such, it's unnatural; so it must be invented by humans; so in a sense it's a self-projection. But I don't think it's hubristic. Now, if you want to talk hubristic, look at Three Gorges Dam. But that's a projection of the politician, not the engineer.

Hubris depends on cultural standards. Back in the early 1800's, the idea of making a railroad engine go at 40 MPH was the height of hubris--except to the engineers. Today, hubris isn't even an issue in trains, cars, airplanes, even rockets. No one says, "Isn't NASA hubristic to try to make rockets go faster than 10,000 MPH?"

But engineering, and to some extent engineers, are divorced from cultural standards. An engineer doesn't ask, "Is it hubristic?" but, "Is it practical?" From the outside, this can look like either hubris or humility--depending on the observer, not the engineer.

As for unnecessary, we'll have to wait till we know more about the practical value. But I hope I can convince you that it's reasonable to think that the practical value might be high. (See the Feasibility email.)

Chris


June 19, from Bill Atkinson to Chris Phoenix
Subject: Re: Intro and loose ends Re: Review Response

Hi Chris,

You can imagined me blackened and smoking, having just picked myself up off the floor; you keep blowing me out of my chair. I'm so glad we're taking the time to E-mail each other: I can feel my head stretch hour by hour. At this point I'm going to go for a run and think about some of your points. More later.

B.

PS. You heard about the agnostic-dyslexic-insomniac who stayed awake all night wondering if there was a Dog? (Dyslexia all through our family)


June 19, from Bill Atkinson to Chris Phoenix
Subject: FYI

Chris: here's my most recent posting on The Well -

I've had the good fortune over the last week to develop a parallel dialogue on some of these points with Mr Chris Phoenix, who by day is a mild-mannered imbedded-software engineer and by night puts on his superhero costume and flies off to make detailed calculations about molecular assemblers. We started off by beating each other up on various points, moved to a grudging mutual respect, and are now (I think) on the brink of a very exciting synthesis of ideas. Anthropologists call the process acculturation, though it often feels like a very noisy and painful collision.

My position in the book Nanocosm is that most of the nanobot crew, along with their fellow travellers the corpsicle people, are off in la-la land, doing endless calcs and getting no nearer to a real device. I'm not convinced I was wrong yet: there are many points I made in the book that have not been fully answered to my mind. But I'm starting to suspect that with certain modifications, the nanoboosters could make contributions to legitimate nanotechnology - giving vision to the traditionalists' spadework, while informing their own work with more discipline and rigor.

- I'll send you some of the comments on this - I can also post your own response(s) if you like. That'll at least save you a tenner.

Best

Bill


June 21, from Chris Phoenix to Bill Atkinson
Subject: Re: FYI

This is a very encouraging start. I look forward to addressing the rest of the points. Either I can read the book again and address them chronologically, or (which is probably faster) you can ask them in the order you're most interested.

Yes, I'd like to see the Well discussions. Thanks!

More discipline and rigor... the rigor of MNT work varies widely, even within the same author. Sure, a lot of the stuff is blue-sky daydreaming. But a lot of it isn't. I predict that you'll be surprised to find how much of it is already backed up by rigor. Of course, some of it is backed up by rigorous *theory* without experiment. But some of the theory is quite reasonably extrapolated from experiment. I think it'll have to be assessed case by case--a big job. But even if it's unsupported theory, it's still good for giving vision; there are a lot of areas where the theory is not brittle and will work even if it has to be tweaked.

I used to be an embedded software engineer; I quit a few years ago. Sorry if I said something misleading. I worked at Electronics for Imaging, doing high-end embedded software, for six years. Then I quit to do dyslexia correction and research. Now I'm spending all my time on CRN. And yes, I consider this dialog as CRN business. It's important to establish whether nanobots can really work, and if so, what they might be capable of. (Would you consider CRN a neutral site for posting our dialog?)

I got another email from Fouts; it seems that you are exactly right in your understanding of what he meant to say. He meant to include the neuron cell bodies. So either Fouts doesn't know what "white matter" means, or I don't, or there are two usages. I'm still researching to learn which, but I've found at least one reference to the meaning I thought it had. At this point, I'm thinking of deleting that complaint from the body of the review entirely, with an asterisk'd footnote saying that I removed an unwarranted criticism of you, since you interpreted Fouts correctly, and a clarification of what I originally wrote. Unfortunately I may not be able to do this till Monday.

Chris


[A few emails are omitted, where Bill and Chris discussed the logistics of posting this dialog, and Chris's correction of the "white matter" question in his review. This message, from Bill, sums it up pretty well.]

June 27, from Bill Atkinson to Chris Phoenix
Subject: Re: Intro and loose ends Re: Review Response

Hi Chris! Herewith at least the start of my responses to your last notes.

I like your idea to flag items commented on later in the dialogue with a mark of some kind - maybe a line drawing of a Tennessee wrassle between an engineer and a science writer? Or, here's an alternative possibility: run all the original text as is, with editorial comments where necessary in square brackets. For example, you could insert a note saying "comment since verified/amended in personal communication with _____" This would keep the dialogue fresh and avoid the impression that we've all been running around ex post facto, shoring up our positions! Above all I want to retain what we've created here: the feel of a work in process - the acculturation I refer to at one point, where extreme opposites start to grope toward common ground. Like a live debate before an audience: a work in progress, rather than an exchange of doctrines in pamphlet form.

The Fouts material seems increasingly irrelevant to our main points. As he says, he himself isn't a neurologist; nor are we. So let's go with what we've got, and move on. Interesting stuff, but tangential.

Thanks for the chalk-talk on covalent bonds. Perhaps because I interviewed so many nanotechnologists who came to their research via chemistry, I tend to think of nanotech, at least today's nanotech, as chemically based. Interestingly enough, I'm getting feedback from several of my chemist interviewees that there's a push on, at least within the US NNI, to fund nanotech R&D that's done mostly (or even only!) by physicists.

In the book I wrote glowingly about nanotech's ability to synthesize a variety of disciplines into something science hasn't had for several hundred years: a unified view of nature - a single discipline, looking at a single thing. This might still happen; but I may well have underestimated the foot-dragging by existing disciplines. There's an enormous amount of vested interest within those disciplines in keeping themselves walled off, and regarding other disciplines as unworthy competitors for funding.

My next response will, at your request, focus on some of my own areas of expertise, including marketing communications. I have a hunch this will surprise you.

Best

Bill


June 27, from Bill Atkinson to Chris Phoenix
Subject: Re: Feasibility and desirability Re: Review Response

Hi Chris,

One thing I didn't boggle at was the nanoscale frictionless bearing. It's already demonstrated in chemicals called rotaxanes, to which I refer in the book. So yes, there's a precedent for the actual improbable (as opposed to the plausible impossible). On the high nanoscale / low microscale border, the bacterial motors that power whiplike or rotational flagella would be unlikely if friction loss were any higher than negligible, or (another way of stating the same thing, I suppose) oscillatory or rotational efficiency were anything less than extreme - 100% less delta.

I will grant you that sheer fiddliness, by itself, is not necessarily a barrier to new technology. Even steam, when you examine it historically, was incredibly complex. Engineers in our grandfathers' or great-grandfathers' day weren't less intelligent, or even less educated, than we: they just worked on different data sets. Try finding a crew today who could break down, diagnose, repair, and reassemble a Pacific 351 locomotive in six hours, a turnaround that was routinely done in a good shop c.1938. Or locate a good flint-knapper who could take a lump of chert and give you a laurel-leaf point that would kill a mammoth.

My problem with the MA technology you describe is that it's still completely imaginary: all calc and no grease. Workable technology, indeed any technology worth the name, has a fairly short cycle between drawing board and lathe: between idea and trial. In fact the better the technology, the shorter the oscillatory period. It's a tennis game: imagine/try/iterate. MA work seems to have stalled in the Imagine half-cycle. Thus denying itself any feedback, it's evolved wilder and wilder designs - absolutely none of which have been put to the test. It was my growing annoyance in realizing this that really led to my complete loss of patience with Eric Drexler. The guy really has dispensed, it seems to me, with the necessary reality checks.

As have you. You tell me your recent work has "solved problems." No: it's only done sums and solved equations. A true solution requires demonstration: and that in turn demands that fateful encounter with reality, in the person of the nanocosm. Elsewhere both you and Drexler like to cite the Manhattan Project, with its endless calcs and forecasts. But the Project met the description I set out above, for an actual technology: a high-frequency iteration between theory and practice, paper and nature, screen and reality. Kept isolated, untested and therefore unproven, the greatest calcs in the world are infertile. I say, with Gibbon's 1781 critic: "Another damned, thick, square calculation! Always scribble, scribble, scribble! Eh! Mr Phoenix?"

No doubt you'll say Yes, but it's a preliminary: we're coming to the shop work. Good, then: I'm glad to hear it. Do it. Until you do, you won't know which of your calculations are workable, and which just seem workable - and for all their internal elegance, are either unworkable or simply untrue. I keep coming back to this point, only to be told: Give us time - five years, ten years, fifty years. But something admitted to be vital, and not yet done, in a way suspends dialogue. Come back to me when you start your shop work. Till then I'll stay a skeptic.

That being said, I have to admit - Gad, this is dragged out of me! - that some of your ideas are conceptually fascinating. I like the way the extreme complexity and intricacy of your world view's design and construction may be - I say, May Be! - offset by the extreme simplicity of its operating methodology. There seems a parallel between your view here and the main point I was trying to make in my CA discussion: ie. that at the nanoscale, manufacturing success absolutely demands a stripped-down, cut-rate, compressed, streamlined minimality in directive algorithms. Otherwise the whole concept of the MA collapses under the weight of its own complexity.

Another reality-based question. Can you really create a nanoscale clean room, without a single bit of unwanted crud in it, ever? Because a single atom in the wrong place at the wrong time would gum up the works. This may be your tallest technological order. Again, I'll believe when I see. But I grant (aghh! the tooth is pulled) it may be conceptually possible. Nice calc.

But again: Why bother? The super-strong materials to which you refer are already being achieved by self-assembly, using sputtering (AIST Tsukuba) or other techniques for self-deposition and self-organization (Integran Technologies, Toronto). It's as if you've designed a nutcracker that works by firing a hammer into orbit, then falls to Earth to smash the walnut. Even if it's possible, why bother? It's unnecessarily complicated. Worse, even from the eng-calc viewpoint, it's inelegant - it doesn't tap into that organizing information that seems evenly dissolved throughout nature. Why compel when you can persuade? The molecular assembler seems nothing more than a steam-propelled gondola, or that orbital nutcracker.

That's assuming, which I do not believe, that it can ever be shown to work. For example, I don't see how you can claim the nanoassembler will have universal application when it will work only on, and with, stiff materials. "Wide variety of parts and properties"? Only if they're stiff! (You can paint my Ford any color, as long as it's black.)

We could throw rocks at each other forever on this one. That's why I think my later response is going to surprise you. I think this whole issue could give you folks your only workable chance to get the respect that the mainstream scientific communities, and I too, have so far denied you.

I know, I know - What a tease!

Best

Bill

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