There’s a fundamental disconnect between a machine, and a programmable machine. A machine is presumed to do one operation, and do it well. A machine is like a shovel or a lever. It’s not unnecessarily complicated, it’s not terribly difficult to build, and it can usually work with pretty wide failure tolerances. This is why you just want a shovel and not a combination shovel/toaster when you have to dig a hole.
A programmable machine is like a computer. It is capable of performing many different operations depending on what kinds of inputs it receives. Programmable machines are complicated, difficult to construct, and can fail in both very subtle and very spectacular ways.
We can also imagine the distinction between a set of wood-working tools and a 3d-printer. A hammer is a machine. A reprap is a programmable machine.
If the question we’re trying to answer is, can we build a protein hammer, the answer is probably yes. But if we make a bunch of simple protein hammers, then we have to solve the very difficult problem of how to ensure that each tool is in the right place at the right time. A priori , there’s no molecular carpenter ensuring that those tools happen to encounter whatever we’re trying to build in any consistent order.
That’s a very different problem than the problem of “can we make a protein 3-D printer”, that has the ability to respond to complicated commands.
I’m not sure which of these situations is the one being advocated for by MNT proponents.
Again, you’re trying to argue against nanoassemblers. If you’re trying to say that nanoassemblers will be difficult to build, I entirely concede that point! If they weren’t, we’d have them already.
Nevertheless, we have today progammable machines that are built with components of nanoscopic size and are subject to weird quantum effects, that nevertheless have billions of components and work relatively smoothly. Such devices would have been thought impossible just a few decades ago. So just because something would be immensely complex is no argument for its impossibility.
However, as I said, this is all beside the point, since MNT does not strictly require nanoassemblers. A nanofactory would be built of a large set of simple tools as you describe—each tool only doing its own thing. This is much like biology where each enzyme is designed to do one thing well. However, unlike biology, the way you would go about designing a nanofactory would be similar to an assembly line. Components would be created in controlled conditions and probably high vacuum (possibly even cryogenic temperatures, especially for components with unstable or metastable intermediaries). Power would be delivered electrically or mechanically, not through ATP.
Why not just do it like biology? Well, because of different design constraints. Biological systems need to be able to grow and self-repair. Our nanofactory will have no such constraints. Instead, the focus would be on high throughput and reconfigurability. Thus necessitating a more controlled, high-power environment than the brownian diffusion-reaction processes of biology.
Great, so this I think captures a lot of the difficulty in this discussion, where there’s a lot of different opinions as to what exactly constitutes MNT. In my reading of Drexler so far, he appears to more or less believe that early Nanotech will be assembled by coopting biological asssemblers like the ribosome. That’s specifically the vision of MNT that I’ve been trying to address.
Since you seem not to believe in that view of MNT, do you have a concise description of your view of MNT that you could offer that I could add to the discussion post above? I’m particularly interested in what environment you imagine your nanoassembler operating.
To add to my reply above, one approach for discussion about the specifics of future technology is to take an approach like Nanosystems does: operate within safe limits of known technology and limit concepts to those that are more-or-less guaranteed to work, even if they are probably inefficient. In this way, even though we acknowledge that our designs could not be built today, and future technology will probably choose to build things in an entirely different way, we can still have a rough picture of what’s possible and what isn’t.
It shows an ‘assembly line for molecules’. Of course, there are many questions that are left unanswered. Energy consumption, reconfigurability, throughput. It’s unclear at all if the whole thing would actually be an improvement over current technology. For example, will this nanofactory be able to produce additional nanofactories? If not, it wouldn’t make things any cheaper or more efficient.
However, it does serve as a conceptual starting point. And indeed, small-scale versions of the technology exist right now (people have automated AFMs that are capable of producing atomic structures; people have also used AFMs to modify, break, and form chemical bonds).
there’s a lot of different opinions as to what exactly constitutes MNT
There’s two different discussions here. One is the specific form the technology will take. The other is what it will be capable of doing. About the latter, the idea is to have a technology that will be able to construct things at only marginally higher cost than that of raw materials. If MNT is possible, it will be able to turn dirt into strawberries, coal into diamonds, sand into computers and solar panels, and metal ore into rocket engines. Note that we are capable of accomplishing all of these feats right now; it’s just that they take too much time and effort. The promise of MNT and why it is so tantalizing is precisely because it promises, once functional, to reduce this time and effort substantially.
I’m more than willing to debate about the specifics of the technology, although we will both have to admit that any such discussion would be incredibly premature at this point. I don’t think a convincing case can be made right now for or against any hypothetical technology that will be able to achieve MNT.
I’m also more than willing to debate about the fundamental physical limits of construction at the nanoscale, but in that case it is much harder to refute the premise of MNT.
There’s a fundamental disconnect between a machine, and a programmable machine. A machine is presumed to do one operation, and do it well. A machine is like a shovel or a lever. It’s not unnecessarily complicated, it’s not terribly difficult to build, and it can usually work with pretty wide failure tolerances. This is why you just want a shovel and not a combination shovel/toaster when you have to dig a hole.
A programmable machine is like a computer. It is capable of performing many different operations depending on what kinds of inputs it receives. Programmable machines are complicated, difficult to construct, and can fail in both very subtle and very spectacular ways.
We can also imagine the distinction between a set of wood-working tools and a 3d-printer. A hammer is a machine. A reprap is a programmable machine.
If the question we’re trying to answer is, can we build a protein hammer, the answer is probably yes. But if we make a bunch of simple protein hammers, then we have to solve the very difficult problem of how to ensure that each tool is in the right place at the right time. A priori , there’s no molecular carpenter ensuring that those tools happen to encounter whatever we’re trying to build in any consistent order.
That’s a very different problem than the problem of “can we make a protein 3-D printer”, that has the ability to respond to complicated commands.
I’m not sure which of these situations is the one being advocated for by MNT proponents.
Again, you’re trying to argue against nanoassemblers. If you’re trying to say that nanoassemblers will be difficult to build, I entirely concede that point! If they weren’t, we’d have them already.
Nevertheless, we have today progammable machines that are built with components of nanoscopic size and are subject to weird quantum effects, that nevertheless have billions of components and work relatively smoothly. Such devices would have been thought impossible just a few decades ago. So just because something would be immensely complex is no argument for its impossibility.
However, as I said, this is all beside the point, since MNT does not strictly require nanoassemblers. A nanofactory would be built of a large set of simple tools as you describe—each tool only doing its own thing. This is much like biology where each enzyme is designed to do one thing well. However, unlike biology, the way you would go about designing a nanofactory would be similar to an assembly line. Components would be created in controlled conditions and probably high vacuum (possibly even cryogenic temperatures, especially for components with unstable or metastable intermediaries). Power would be delivered electrically or mechanically, not through ATP.
Why not just do it like biology? Well, because of different design constraints. Biological systems need to be able to grow and self-repair. Our nanofactory will have no such constraints. Instead, the focus would be on high throughput and reconfigurability. Thus necessitating a more controlled, high-power environment than the brownian diffusion-reaction processes of biology.
Great, so this I think captures a lot of the difficulty in this discussion, where there’s a lot of different opinions as to what exactly constitutes MNT. In my reading of Drexler so far, he appears to more or less believe that early Nanotech will be assembled by coopting biological asssemblers like the ribosome. That’s specifically the vision of MNT that I’ve been trying to address.
Since you seem not to believe in that view of MNT, do you have a concise description of your view of MNT that you could offer that I could add to the discussion post above? I’m particularly interested in what environment you imagine your nanoassembler operating.
To add to my reply above, one approach for discussion about the specifics of future technology is to take an approach like Nanosystems does: operate within safe limits of known technology and limit concepts to those that are more-or-less guaranteed to work, even if they are probably inefficient. In this way, even though we acknowledge that our designs could not be built today, and future technology will probably choose to build things in an entirely different way, we can still have a rough picture of what’s possible and what isn’t.
For example, take this video: http://www.youtube.com/watch?v=vEYN18d7gHg
It shows an ‘assembly line for molecules’. Of course, there are many questions that are left unanswered. Energy consumption, reconfigurability, throughput. It’s unclear at all if the whole thing would actually be an improvement over current technology. For example, will this nanofactory be able to produce additional nanofactories? If not, it wouldn’t make things any cheaper or more efficient.
However, it does serve as a conceptual starting point. And indeed, small-scale versions of the technology exist right now (people have automated AFMs that are capable of producing atomic structures; people have also used AFMs to modify, break, and form chemical bonds).
There’s two different discussions here. One is the specific form the technology will take. The other is what it will be capable of doing. About the latter, the idea is to have a technology that will be able to construct things at only marginally higher cost than that of raw materials. If MNT is possible, it will be able to turn dirt into strawberries, coal into diamonds, sand into computers and solar panels, and metal ore into rocket engines. Note that we are capable of accomplishing all of these feats right now; it’s just that they take too much time and effort. The promise of MNT and why it is so tantalizing is precisely because it promises, once functional, to reduce this time and effort substantially.
I’m more than willing to debate about the specifics of the technology, although we will both have to admit that any such discussion would be incredibly premature at this point. I don’t think a convincing case can be made right now for or against any hypothetical technology that will be able to achieve MNT.
I’m also more than willing to debate about the fundamental physical limits of construction at the nanoscale, but in that case it is much harder to refute the premise of MNT.
What about using lazors? (<- intentionally signalling my lack of understanding but wanting to feel participating when the grownups talk anyway)