Next week – on the 26th March – I’m participating in a discussion event sponsored by the thinktank Policy Exchange at NESTA, in London. Also on the panel is K. Eric Drexler, the originator of the idea of nanotechnology in its most expansive form, as an emerging technology which, when fully developed, will have truly transformational effects. It will, in this view, allow us to make pretty much any material, device or artefact for little or no cost, we will be able to extend human lifespans almost indefinitely using cell-by-cell surgery, and we will create computers so powerful that they will host artificial intelligences greatly superior to those of humans. Drexler has a new book coming out in May – Radical Abundance: How a Revolution in Nanotechnology Will Change Civilization. I think this view overstates the potential of the technology, and (it shocks me to realise), I have been arguing this in some technical detail for nearly ten years. Although I have met Drexler, and corresponded with him, this is the first time I will have shared a platform with him. To mark this occasion I have gone through my blog’s archives to make this anthology of my writings about Drexler’s vision of nanotechnology and my arguments with some of its adherents (who should not, of course, automatically be assumed to speak for Drexler himself).
To begin with, one should understand Drexler’s position by reading his own words. His first publication on the subject was a short paper in the journal Proceedings of the National Academy of Sciences, in 1981, Molecular engineering: An approach to the development of general capabilities for molecular manipulation. This paper demonstrated the possibility of artificial molecular machines by analogy with the protein-based molecular machines of biology, and argued that protein engineering is the natural route by which a second generation of artificial molecular machines, more powerful than their natural precursors could be made.
Drexler’s next publication was perhaps his most influential; this was his 1986 popular science book Engines of Creation: the coming era of nanotechnology. This explored the consequences of the molecular assemblers that he argued could be made from the second generation molecular machines, able to make virtually anything consistent with the basic laws of physics, atom-by-atom, with atomic precision. One consequence would be cell repair machines able to halt and reverse the effects of ageing and disease, leading to indefinite human lifespans.
Engines of Creation was not a technical book, so it did not include much more in the way of detail of how these universal assemblers would be made. This detail was provided in Drexler’s 1992 book, Nanosystems: Molecular Machinery, Manufacturing, and Computation. It’s difficult to imagine a book more different to Engines of Creation than Nanosystems. It’s almost gratuitously dry and technical, a textbook for a yet-to-be-developed technology, based on the principle that “molecular manufacturing applies the principles of mechanical engineering to chemistry”.
My own thinking on nanotechnology – summarised initially in my 2004 book Soft machines: nanotechnology and life – was at the same time inspired by Drexler’s work and a reaction against it. Like Drexler, I was fascinated by the example that cell biology provided of intricate, molecular scale machines. But I was also struck by the insights that the new single molecule biophysics was providing (using the new tools of nanoscience) – insights that stressed that the principles used by the molecular machines were not the principles of mechanical engineering, but a quite alien set of design principles optimised for the peculiar physics of the warm, wet, nanoscale world – the principles of soft nanotechnology.
I dealt with the question of what nanotechnology should learn from biology in this blog post – What biology does and doesn’t prove about nanotechnology – which was a riposte to some heated discussions on the blogs of the time. I came back to this question with a more reflective discussion of the same themes in my column in Nature Nanotechnology -
Right and wrong lessons from biology.
Moving to my criticisms to the vision of nanotechnology presented in Nanosystems, the context can be found in this piece: Molecular nanotechnology, Drexler and Nanosystems – where I stand. In making and doing I argued that matter is not digital, responding to quite extensive discussion of that post in bits and atoms. I outlined some specific technical issues in Six challenges for molecular nanotechnology.
My most widely circulated critique was published in the US magazine IEEE Spectrum – Rupturing the nanotech rapture. By this time Drexler’s vision of radical nanotechnology had become a central part of the belief package of transhumanists and proponents of the secular eschatology of the technological singularity, as most notably and influentially popularised by Ray Kurzweil in his book The Singularity is Near. My article was part of a special issue exploring, mostly from a critical perspective, this idea (misguided as it is, in my opinion). Nanobots, nanomedicine, Kurzweil, Freitas and Merkle was a response to criticisms of the IEEE Spectrum article.
Lately, Drexler has been writing on his own blog Metamodern. From there it is clear that we agree about some things – the importance of the “soft” route to radical nanotechnology in the near future, the achievements and potential of DNA nanotechnology, for example – and remain in disagreement about others. I look forward to discussing these issues with him on Tuesday.