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.
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.
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.
Richard Smalley is the canonical white haired Nobel Laureate who disagrees strongly with the idea of MNT as Drexler outlines it.
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:
Evolution has just been dealt its death blow. After reading Origins of Life with my background in chemistry and physics, it is clear that biological evolution could not have occurred.
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..
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.
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.
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 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 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.
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.
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.
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.
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 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 be interested to see this.
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.