Eric Drexler is quoted in Adam Keiper’s report from the NRC nanotechnology workshop in DC as saying:
“What’s on my wish list: … A clear endorsement of the idea that molecular machine systems that make things … with atomic precision is a natural and important goal for the development of nanoscale technologies … with the focus of that endorsement being the recognition that we can look at biology, and beyond…. It would be good to have more minds, more critical thought, more innovation, applied in those directions.”
I almost completely agree with this, particularly the bit about looking at biology and beyond. Why only almost?. Because “systems that make things” should only be a small part of the story. We need systems that do things – we need to process energy, process information, and, in the vital area of nanomedicine, interact with the cells that make up humans and their molecular components. This makes a big difference to the materials we choose to work with. Leaving aside, for the moment, the question of whether Drexler’s vision of diamondoid-based nanotechnology can be make to work at all, let’s ask the question, why diamond? It’s easy to see why you would want to use diamond for structural applications, as it is strong and stiff. But its bandgap is too big for optoelectronic applications (like solar cells) and its use in medicine will be limited by the fact that it probably isn’t that biocompatible.
In the very interesting audio clip that Adam Keiper posts on Howard Lovy’s Nanobot, Drexler goes on to compare the potential of universal, general purpose manufacture with that of general purpose computing. Who would have thought, he asks (I paraphrase from memory here), that we could have one machine that we can use to do spreadsheets, play our music and watch movies on? Who indeed? … but this technology depends on the fact that documents, music and moving pictures can all be represented by 1’s and 0’s. For the idea of general purpose manufacturing to be convincing, one would need to believe that there was an analogous way in which all material things could be represented by a simple low level code. I think this leads to an insoluble dilemma – the need to find simple low level operations drives one to use a minimum number – preferably one – basic mechanosynthesis step. But in limiting ourselves in this way, we make life very difficult for ourselves in trying to achieve the broad range of functions and actions that we are going to want these artefacts for. Material properties are multidimensional, and it’s difficult to believe that one material can meet all our needs.
Matter is not digital.