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leplen comments on For FAI: Is "Molecular Nanotechnology" putting our best foot forward? - Less Wrong Discussion
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Comments (117)
While this may be a settled point in your mind, it is not in general a settled point in the mind of your audience. Inasmuch as you're trying to convince other people of your beliefs, it's best to meet them where they are, and not ask them to suspend their sense of disbelief in directions that are more or less orthogonal to your primary argument.
MNT is not widespread in the meme pool. Inasmuch as FAI assumes or appears to rely on MNT, it will pay a fitness cost in individuals who do not subscribe to the MNT meme.
Now maybe FAI is particularly convincing to people who already have the MNT meme, and including MNT in possible FAI futures gives it a huge fitness advantage in the "already believes MNT" subpopulation. Maybe the trade-off for FAI of reduced fitness in the meme pool at large (or the computational-materials-scientist meme-pool) is worth it in exchange for increased fitness in the transhumanist meme pool. I don't know. I certainly haven't done nearly the work publicizing FAI that you have, and obviously you have some idea of what you're doing. I'm not trying to argue that it should be taken out, or never used as an example again. I will say that I hope you take this post/argument as weak counter-evidence on the effectiveness of this particular example, and update accordingly.
Eliezer linked to the Drexler book and dissertation and he probably trusts the physics in it. If you claim that the physics of nanotech is much harder than what is described there, then you better engage the technical arguments in the book, one by one, and believably show where the weaknesses lie. That's how you "unsettle" the settled points. Simply offering a contradictory opinion is not going to cut it, as you are going to lose the status contest.
Given the unfathomably positive reception of the grandparent allow me to quote shminux's reply for support and emphasis.
The opening post took the stance "but seeing all the physics swept under the rug like that sets off every crackpot alarm I have.". Eliezer provided a reference to a standard physics resource that explains the physics and provides better arguments than Eliezer could hope to supply (without an unrealistic amount of retraining and detouring from his primary objective.) The response was to sweep the physics under the rug and move to "you have to meet me where I am". Unsurprisingly, this sets off every crackpot alarm I have.
As an alternative to personally engaging in the technical arguments at the very least he could reply with reference to another authoritative source such as another textbook or several people with white hair and letters before their name. That sort of thing can support a position of "that science is disputed" or, if the hair is sufficiently white and the institutional affiliations particularly prominent it could potentially even support "Drexler is a crackpot too!". But given that the dissertation in question was for MIT that degree of mainstream contempt seems unlikely.
I will be happy to engage Drexler at length when I get the chance to do so. I have not, in the last 3 days, managed to buy the book and go through the physics in detail. I hope that failure is not enough to condemn me as not acting in good faith. I made it through the first couple chapters of the dissertation, but it read like a dissertation, which is to say lots of tables and not much succinct reasoning that I could easily prove or disprove. There seemed to be little point in linking to "expert rebuttals" because presumably these would not be new information, though Richard Smalley is the canonical white haired Nobel Laureate who disagrees strongly with the idea of MNT as Drexler outlines it.
This post was not intended primarily as a discussion on whether MNT was true or not. If people consider that an important discussion, I'll be happy to participate in it and lend whatever expertise I may or may not have. I'll be happy to buy Nanosystems and walk us all through as much quantum mechanics as anyone could ever want. This was emphatically not my point however. I don't have a strong opinion on whether MNT is true. I will freely admit to not having personally done the research necessary to come to a confident conclusion one way or the other. I am confident that it's controversial. It's not something one hears mentioned in materials science seminars, it doesn't win you any grants, you wouldn't put it in a paper. While it may still be true, I don't think it's well-established enough that it's the sort of truth you can take for granted.
I personally would not, when giving an explanation for some phenomenon, ask you to take for granted without at least a citation the following statement. "The ground state energy of a system of atoms can be determined exactly without knowing anything about the wave function of the system and without knowing the wave functions of the individual electrons." I would not expect anyone reading that statement to be able to evaluate its truth or falsehood without a considerable diversion of energy. I would anticipate that patient readers would be confused, and some people might give up reading altogether because I was stating as fact things they had no good way of verifying.
However, the Hohenberg-Kohn theorems are demonstrably true, and have been around for 50 years. That doesn't make them obvious. If I skip a step in a proof or derivation, it doesn't make the proof wrong, but it is going to make people who care about the math very uncomfortable. When one publishes rigorous technical writing, the goal is precisely to make the inferential gaps as small as possible, to lead your skeptical untrusting readers forcefully to a conclusion, without ever confusing them as to how you got from A to B, or opening the door to other explanations.
Absolutely not, and I think this occasioned a useful discussion. But if you have a physics or chemistry background, I for one would greatly appreciate it if you did so (and the Smalley critique, and perhaps Locklin below) and posted your take. Also you don't need to buy the book, you should be able to get a copy at any large university library.
I am no expert in the relevant science, but I take the Smalley argument from authority with a grain of salt, for two reasons.
First, according to wikipedia Smalley was a creationist, and apparently he endorsed an Intelligent Design book, saying the following:
If he underestimated the ability of evolution to create complex molecular machines, perhaps he did the same about human engineering.
Also, the National Academy of Sciences, in its 2006 report on nanotechnology, discussed Drexler's ideas and did not take Smalley's critique to be decisive (not a ringing endorsement either, of course, suggesting further experimental research). Here is a page with the relevant sections.
This critique by Scott Locklin seems mainly to be arguing that Drexler was engaged in premature speculation that was not a useful contribution to science or engineering, and has not borne useful fruit. But he also attacks nuclear fusion, cancer research, and quantum computing (as technology funding target) for premature white elephant status, which seem like good company to be in for speculative future technology.
He says that there may be technologies with similar capabilities to those Drexler envisions eventually, but that Drexler has not contributed to realizing them, and suggests that Drexler made serious physics errors (but isn't very clear about what they are).
I would be interested in knowing about the technological limits, separately from whether they will be reached anytime soon, and whether Drexler's contributions were any good for science or engineering..
Okay. I'll try and do this. I'm mildly qualified; I'm finishing up a Ph.D. in computational materials science. It will take me a little while to make time for it, but it should be fun! Anyone else who is interested in seeing this discussion feel free to encourage me/let me know.
I would be interested to see this.
I would love to see a critique that started "On page W of X, Drexler proposes Y, but this won't work because Z". Smalley made up a proposal that Drexler didn't make ("fat fingers") and critiqued that. If there's a specific design in Nanosystems that won't work, that would be very informative.
I would very much like to see this. Sounds like another discussion-level post would be in order.
Thanks!
Certainly not (perceived as acting in bad faith). Instead, that particular comment was a misstep in dance of rationality. It was worth correcting with emphasis only because many other people were making it too (via excessive upvoting). As Eliezer noted there would be a big improvement if you said "oops but still consider the PR implications".
Like Carl I would appreciate someone else analysing the physics in Drexler's dissertation and book thoroughly and giving a brief summary of key findings and key concepts.
For my part what I do take for granted is that DNA based machines can be used to create arbitrarily complex impacts on the environment. The question of precisely how much smaller than DNA based cells it is possible to make machines is a largely incidental concern.
This entire thread is about the PR implications. There's a reason I titled it "Is MNT putting out best foot forward" and not, "Is MNT true?"
I don't care about MNT. I do care about FAI. I regret deeply that this discussion has become focused on whether or not MNT is true, which is a subject I don't really care about, and has gotten away from, "Is MNT a good way to talk about FAI" which is a subject I care a lot about.
Also I have some worries about the pattern "X is unsupported! What, you have massive support for X? Well talking about X is still bad publicity, really I'm concerned for how this makes you look in front of other people." I'll consider an 'oops, I retract my previous argument, but...' followed by that shift, but not without the 'oops'. Otherwise I do update on X possibly being bad publicity, but not in a being-persuaded way, more of an okay-I've-observed-you way.
I don't consider Drexler's work to be "massive support" for MNT. I think that MNT is controversial. I think that one shouldn't introduce controversial material in a discussion unless you absolutely have to for some of the same reasons I think that Nixon being a Quaker and Republican is a bad example.
I honestly wasn't sure when I posted this whether anyone else here would feel the same way about MNT being non-obvious and controversial. It does seem safe to say that if MNT is controversial on LW, which is overwhelmingly sympathetic to transhumanist ideas, then it's probably even less popular outside of explicitly transhumanist communities.
Drexler gets the physics right. It's harder to evaluate the engineering effort needed. Eliezer's claims about how easy it would be for an FAI to build MNT go well beyond what Drexler has claimed.
I'm fairly sure I know more about MNT than Eliezer (I tried to make a career of it around 1997-2003), and I'm convinced it would take an FAI longer than Eliezer expects unless the FAI has very powerful quantum computers.
Why do you expect this to help? What nanotech computations would a "very powerful quantum computer" accomplish so much faster than a classical computer? Or do you mean something like an "analog" quantum computer, also known as a "quantum simulator", which solves the Schrodinger equation by simulating the Hamiltonian and its evolution, rather than the "ordinary" digital quantum computer, which speeds up numerical algorithms?
Anything that makes the Schrodinger equation tractable would make me much less confident of my analysis.
How did natural selection solve this problem without quantum computers or even intelligence, and why can't an AI exploit the same regularity even faster?
Natural selection used trial and error. An AI would do that faster and with fewer errors.
Offhand, I would expect analog quantum simulators to come before digital quantum computers, given how they are already naturally everywhere, anyway, just not in a well-controlled way. Sort of like birds were a living proof that "heavier-than-air flying machines" are possible. This year-old Nature review seems to show a number of promising directions.
Estimating how long a strong AI takes to design molecular nanotechnology requires knowledge of molecular nanotechnology, knowledge of recursive artificial intelligence and knowledge of computation. This is particularly the case since most of the computation required to go from a recursively-self-improving-AI-seed to nanotech is going to be spent on the early levels of self improving, not the nanotech design itself.
The "unless the FAI has very powerful quantum computers" caveat gives a rather strong indication that your appeals to your own authority are less trustworthy with respect to AI and computation than they are about MNT (for reasons alluded to by shminux).
There are some problems for which knowledge of the problem plus knowledge of computation is sufficient to estimate a minimum amount of computation needed. Are you claiming to know that MNT isn't like that? Or that an AI can create powerful enough computers that that's irrelevant?
Appeals to authority about AI seem unimpressive, since nobody has demonstrated expertise at creating superhuman AI.
Perhaps my token effort at politeness made me less than completely clear. That wasn't an appeal to AI authority. That was a rejection of your appeal to your own personal authority based on the degree to which you undermined your credibility on the subject by expressing magical thinking about quantum computation.
You just appealed to your own authority about molecular nano-technology. When can I expect you to announce your product release? (Be consistent!)
Magical thinking? I intended to mainly express uncertainty about it.
I don't expect appeals to authority to accomplish much here. Maybe it was a mistake for me to mention it at all, but I'm concerned that people here might treat Eliezer as more of an authority on MNT than he deserves. I only claimed to have more authority about MNT than Eliezer. That doesn't imply much - I'm trying to encourage more doubt about how an AI could take over the world.
Can you provide more detail and maybe give some examples?
From this paper, page 26:
Has Drexler said anything which implies that step 4 would succeed without lots of trial and error?
I'd like to address just the claim here that you could provide instructions to a nanosystem with a speaker. If we assume that the frequency range of the speaker lines up with human hearing, and that our nanosystem is in water, then the smallest possible wavelength we can get from our speaker is on the order of 7cm.
lamda=v / f= 1500 m/s / 20 kHz
How can you provide instructions to a nanosystem with a signal whose linear dimension is on the order of cm? How can you precisely control something when your manipulator is orders or magnitude larger than the thing you're manipulating?
You can get microphones much smaller than 7 cm, and they can detect frequencies way lower than 20 kHz. There's no rule saying you need a large detector to pick up a signal with a large wavelength.
I believe the original comment isn't about the receiver, but about the emitter -- that if you use audible-range sound or even ultrasound, the spatial resolution of the signal will be impossibly large compared to a nanobot. Each nanobot will be able to get the signal, but you won't be able to only communicate with nanobots in a specific part of the body.
This might not be a fatal objection, since you could imagine some sort of protocol with unique addresses or whatnot, but it's an objection.
This isn't about bots, it's about a little tiny factory building your second-stage materials.
You can get the effect of a huge telescope lens with an array of smaller telescopes. Could you get the same effect for sound?
Sure, if you can have all your pieces coordinate and stay coordinated with other. If you do that, you still have a communication problem, just a different one.