Question 1: Tell us about yourself. What is your background, and what current projects are you involved in?

I received an undergraduate degree in Electrical Engineering from Lehigh University in Bethlehem, Pennsylvania, and my Master's Degree in EE from the University of Notre Dame. I first became interested in technology at this point, during the 1970's. During that time, many influential people like the Club of Rome, Meadows and Meadows at MIT, and Stanford biologist Paul Ehrlich predicted that we were soon going to die; we were going to overpopulate ourselves, run out of natural resources, and pollute ourselves to death. They were even predicting food riots by 1985. Then I discovered the work of Gerrard K. O'Neill, who showed how the high frontier of Space removed most of the limits to human growth. When he testified to the house subcommittee on Space and Technology in February of 1978, I went to see him speak.

At a party afterwards, I met Eric Drexler, who had done some impressive work with solar sails and mass drivers. That day, however, he spoke of sub-micro robots that could fit inside cells and had the potential for curing cancer and diseases, and enable extreme longevity-within our lifetimes. I thought he was crazy, but over the years I kept running into him at International Space Development Conferences (first sponsored by L-5, and he started winning me over. In fact, when I was trying to solve a difficult problem in testing integrated circuits, he handed me the answer on a silver plate, but I wasn't ready for molecular electronics. When I read his Engines of Creation, however, he removed any doubts I had had about his nanotechnological vision. However, I also became very depressed about "grey goo". But then L-5 co-founder Keith Henderson told me that we should never be afraid of technology, but that we should control it, and I became more optimistic about ameliorating the negative aspects of nanotechnology. So here I am now, having just completed a project with Chris Phoenix to design a desktop nanofactory.

Question 2: Tell us about your work with Chris Phoenix to develop nanofactories.

It started when I gave a talk titled "Legos to the Stars" at the 1996 International Space Development Conference. In the talk, I noted that self-replicating machines were a critically important component to colonizing space and terraforming planets. The mathematician John Von Neumann had devised two models of self-replicating robots. His first model, of a robot wandering around a warehouse of parts that it could assemble into a copy of itself, was mathematically awkward, and was impossible to build with the technology of the day, so he came up with the concept of cellular automata. This model consisted of a checkerboard of finite state machines that would form patterns of states that would change with respect to their neighbors. My idea was to hybridize the two models, using three-dimensional cubic cells that could attach to and move alongside each other, both at a molecular and a macro scale. I though that the easiest way to experiment in this area, especially in respect to a self-replicating robot, was to use Legos - and it took five years before Greg Chinkjian at Johns Hopkins University did exactly that. The other thing I suggested was to use a modified replication process to expand an assembly line from a single machine. This assembly line would build a membrane which then assemble complex products out of a solution of simple parts. At the time, however, I had absolutely no idea what any of these three machines would look like, but Chris and I have just finished a preliminary design for exactly that.

Question 3: You recently gave a talk at the ISDC regarding on programmable materials. What exactly is kinetic cellular automata?

The idea behind kinematic cellular automata is to get blocks, or cells, which slide over each other and move with respect to their neighbors. A key concept that Chris and I devised is to use scanning probes with shaped tips to manipulate only certain large cubic molecules. This concept is one solution to the "sticky fingers" and "fat fingers" critiques leveled against Drexlerian assemblers. It reduces the problem of building replicating nanofactories to three simple ones:

1. Synthesizing the nanoblocks using chemistry
2. Loading the probe tip; and
3. Connecting a nanoblock to the one that the probe is pressing it against

Question 4: Recently, advocates of molecular machine synthesis have become more aggressive regarding the timetables for the development of molecular manufacturing. What has caused this optimism?

Being a prophet is a difficult job, and they generally kill you for it, especially if you are right. But let me make some very conservative predictions anyway. Moore's Law is an observation based on the principal that if you have tools, then you can use these tools to build better tools. By that logic, and by our experience in the last 40 years, somewhere around 2015 we will be constructing integrated circuits at the molecular level. Within five years after that-ten at the absolute most-, we should be able to build drexlerian assemblers. I can't predict what happens after that.

That is my very conservative prediction. But timeframes for the development of molecular nanotechnology have been shortened because synthetic chemistry has improved. We no longer need to work down at the atomic level because we can use molecules as large as five nanometers. What is happening right now is that top-down methods are meeting bottom-up methods, and that is why Chris Phoenix and I, among others, are confident that powerful molecular manufacturing technologies will emerge sooner rather than later. We won't get mature molecular assemblers right away, but we really don't need low-level molecular manufacturing. In terms of product properties, fifty percent of what molecular assemblers provide can be built much earlier by desktop nanofactories that assemble simple nanoblocks made using synthetic chemistry.

Question 5: Molecular manufacturing proponents have recently replaced the molecular assembler paradigm with the desktop manufacturing paradigm. Has the concept of Eric Drexler's molecular assembler been completely abandoned?

The concept of the molecular assembler hasn't been abandoned; I just think that we need better synthetic chemistry and more precise tools before we can get to molecular assemblers. Keep in mind that the paradigm for molecular manufacturing isn't the only approach; there is more than just one way to achieve an advanced molecular manufacturing capacity.

In the nanofactory that Chris Phoenix and I designed, there are a limited number of blocks floating in solution. This makes the construction of highly heterogeneous molecular structures more difficult, but the construction of more regular structures significantly easier. In contrast, Drexler's bottom-up assemblers start with very simple molecules and works in a vacuum, so one doesn't need to worry about dangling bonds, and can construct a very wide variety of atomically precise structures easier. We want to show that there are many ways to get to molecularly precise structures. Not only does it make it happen faster, but it shows that the "sticky fingers" and "fat fingers" objections are irrelevant.

Question 6: Dr. J. Storrs Hall has proposed the concept of "utility fog". Do you see the creation of some type of "utility fog" as feasible, or even inevitable?

I believe that some form of utility fog is inevitable, although it isn't feasible yet. In my 1996 "Legos to the Stars" I mentioned Josh's work, but I realized at the time that we couldn't build anything like that, even at the macroscale. Manipulating billions of components by grabbing and then releasing them with robot arms is hard even at the macroscale, and is considerably more difficult at the nanoscale.

If, however, you envision utility fog as consisting of very simple molecular cubes with only a three degrees of freedom, then utility fog becomes much more feasible. A number of individuals (such as Mark Yim and Hod Lipson) are doing research in this area of modular robots, using a number of different approaches, though I think their level of complexity is too high. Joseph Michael's and Forrest Bishop's ideas seem much more realistic because they are simpler.

Biology incorporates unicellular organisms that are all the same, but in order to have structure you need some degree of hierarchy and/or specialization. We may not need to do it that way, but in the long term we will probably have to work with some form of hierarchy, simply because it is more efficient.

You don't need full-blown assemblers to have utility fog. The "smart silkscreens" that Chris Phoenix and I have designed could probably build a primitive utility fog.

Question 7: Do we have the necessary precursor tools for molecular machine synthesis? Do we have the computing power necessary to accurately and precisely model complex molecular synthesis?

It depends on what you mean by "precursor". In a sense, we do have the early precursors now. For example, the National Science Foundation is working on an integrated model to simulate a billion atoms. A billion atoms should be enough for building an assembler, so in that sense, we have a precursor. However, we still need to build a few levels of precursors before we get to "full-blown" molecular assembly. There are two problems - knowledge and the laws of physics. There is still much ignorance regarding nanoscale physics, but the better tools that you have, the better our understanding of nanoscale physics will be. Better tools enabled the human genome project to finish way ahead of schedule. So once we have the combination of knowledge and mature nanotools, we will reach the "bend". And we can see how the precursors that we have been proposing will get us to the bend. Once we have a "smart silkscreen", then we will be at the bend. Still only half-way to diamondoid utility fog, or even less, but even half-way is pretty darn impressive. Scary, even.

Building a "smart silkscreen" will be difficult, and we have identified three small steps that we need to get there. The technology is progressing along multiple fronts. Suddenly, we will hit the bend, and some people will panic, because then they will realize that what Eric Drexler predicted 20 years ago will be happening in less than five years.

Question 8: What is your current best estimate regarding timeframes?

It depends on funding. If our plans go according to schedule, then it will be a matter of how complicated we can build the blocks, and how well we can connect them. How well we can connect them depends on two things; one of them is the AFM, which is fairly mature, and the other is the chemistry, which is also mature. Will we be able to use covalent bonds? We think so, but until we've actually done it, we can't be certain. If we succeed, then we will be able to build what we call a "tattoo machine", and then a row of "tattoo machines". Once we can build a one-dimensional row of "tattoo machines" or controllable AFM functionalized tips that can lay down the nanoblocks, just like Eric [Drexler] shows in the last 30 seconds of his video, then we should be able to build an array, which in turn should enable us to build a "smart silkscreen". With a few million dollars, it may take five years for us to that point.

People recognize the nanotech dream, and they see the potential for lots of money, but they won't just want to invest in it, they'll want to own it. This will actually bring it's own set of problems, such as IP deadlocks.

Question 9: During the past decade, has the scientific community become more amenable to concepts of molecular manufacturing?

I think that the scientific community is schizophrenic, because like most people, scientists fear what they don't understand, though they may become fascinated by the parts the do understand. Some members of the scientific community are threatened by Drexler's vision, probably because having to acknowledge that some of their career's endeavors have been a big waste of time is quite painful. I think that is why some scientists are very much against it. Many of Drexler's concepts require extensive thought and reflection before they can be fully understood. The internet helps enormously in this regard - without Google, none of this will happen.

People can examine trends and see where this is going, and that is why nanotechnology is such a sexy word right now. With Artificial Intelligence, people don't know how intelligence works, so the field is currently dead. But useful things came out of AI research, such as intelligent interfaces, voice recognition, and graphic user interfaces, and these things are no longer called AI.

There will be many failed experiments in molecular manufacturing, but that is what capitalism is for. Unfortunately, free enterprise only works with short range goals, and that is why the government needs to get involved. Things are progressing, and this is an exciting time in which to live.

Question 10: What are your plans for the next decade?

By 2015, we will have some pretty impressive tools. If by 2015, we do not have scanning probe arrays and smart silkscreens doing planar assembly, then I will be amazed. Right now, 2020 is where my predictions stop - I've been thinking about nanotech for almost 20 years now, and I feel like one of Henry Ford's mechanics being asked how the automobile will affect dating patterns. I don't know. I wish I did. We will probably finish the human proteome project by the end of this decade, and if that brings the capabilities we think it will, then things will get really interesting. This raises a number of disturbing issues about nanoethics - not the accidental and improbable release of gray goo, nor the intentional and probable use of nanotechnology for illegal and criminal uses. What I really worry about is those aspects of nanotechnology that appear to us to be good, but in reality will dehumanize us.

Take life extension, for example. Life is good, so more life is better, right? But what if I'm wrong, and Leon Kass is right? It gives me nightmares, even though it's not very likely. Something that is even more likely, given our history with women, slaves, and the unborn, is that nanotechnology will make it possible again for one group of people with power to redefine another group of people into subpersons - and they will. We will pay dearly for that mistake. To paraphrase Abraham Lincoln in his second inaugural address, every drop of blood drawn by the slavemaster's whip will need to be repaid in full.

Nanotechnology will bring into focus again the question we've been struggling with for millennia - what does it mean to be human? The problem is that most people have no idea, and it's almost impossible to prove any particular definition - even the correct ones.