MOLECULAR MACHINES

Then comes the second big idea, getting these molecular machines to make copies of themselves, which then make copies of themselves, which then make copies, and so on. This would lead to exponential growth of tiny machines that could then be used to construct macro scale objects from appropriate molecular feedstock’s, and with no wastage. In theory, large, complex structures could be built with atomic precision out of something as robust as diamond, or similar "diamondoid" substances. This is molecular manufacturing.

These ideas were first made widely known by Dr. K. Eric Drexler in his 1986 book Engines of Creation, and have since then found their home at the Foresight Institute (www.foresight.org) and the Institute for Molecular Manufacturing (www.imm.org). Drexler followed up in 1992 with a more technical look at the subject in his book Nanosystems, and is currently working on an updated edition of "Engines".

The potential of such technology to change our world is indeed truly staggering, if it can be realized. Whether it can or not is a subject of debate, sometimes fierce. There is, though, an unassailable argument for the feasibility, in principle, of self-replicating machines that construct things on a molecular level, this being that they already exist—all living things, including ourselves, are built this way. However, Drexler also went on to outline scenarios for making and organizing armies of programmable assemblers. These scenarios are quite different from what we see in nature and here there is certainly more room for debate, especially about matters of complexity, control, and the practicability of making assemblers general purpose (molecular machinery in nature is generally very specific in function, but operates in concert with a host of other machines in a hugely-complex orchestrated effort that is still poorly understood). It has been argued that approaches more akin to those used by nature might be more fruitful than some outlined by Drexler. On the other hand, nature's technology has evolved by chance. Conscious design could in principle allow the creation of machines and materials that nature never produced.

If you accept that general-purpose, programmable assemblers can be constructed, you still have to be careful about predicting what they could make. Building up a three-dimensional structure purely out of diamond, even one with a complex shape, is a relatively simple programming task. Making a steak, which is in turn made of cells, which are themselves vastly complex machines, is another matter altogether. Drexler never made such a suggestion, but it and similar have appeared in the media, which has done nothing to promote public understanding or reasoned debate.

Drexler speculated extensively on the possibilities of molecular machines and saw the potential for not only a dramatic impacts on society the world over, but also dangers. The most famous, and contentious, of these is the prospect of self-replicating assemblers getting out of control and consuming everything in their path to make more copies of themselves, turning everything into”gray goo" in the process. There are good arguments against such an apocalyptic scenario, some of which are presented on the Foresight Institute's own web site (http://www.foresight.org/NanoRev/Ecophagy.html), but a replicating machine could certainly present dangers comparable to a genetically engineered virus, and probably worse (genetically engineered viruses, however, will remain a much more real threat for some time to come). Drexler's recognition of the potential impact and dangers led him to decide that, even if they were still a long way off, it wasn't too early to start preparing for them. A part of the mission of the Foresight Institute, and the research oriented Institute for Molecular Manufacturing, is to do just that. Their guidelines for developing molecular nanotechnology responsibly are outlined at http://www.foresight.org/guidelines/current.html.

Assuming that a molecular assembler, as envisaged by Drexler, can be made (and be made to be economically productive), it won't be for some time yet—even the optimists talk about a period of ten to twenty years or more. However, current work on molecular nanotechnology is not limited to theoretical papers and computer models. The company Zyvex, which bills itself as the world's first molecular nanotechnology company, has recently teamed up with some respected academic groups and attracted government funding to work on building assemblers, starting at the micro scale but, hopefully, moving down to the nanoscale.