First, links to other New Savanna posts bearing on the relationship of mind to matter:
• Galen Strawson on consciousness: the problem we face is simple, we underestimate the subtleties of matter• Has Dennett Undercut His Own Position on Words as Memes? – In which Dennett discovers that metabolism is real
Peter Godfrey-Smith has posted a work in progress, Mind, Matter, and Metabolism (PDF), that bears directly on the issues in play in those two posts. Strawson argues that consciousness presents a problem to materialism only if we have much too simple a view of matter. Our understanding of "brute" matter has changed a great deal since the days of Descartes and Newton. Dennett doesn't express himself in those terms, but his recent reservations about computation are similar in effect. Here PGS speaks to computation (p. 2)
...with the rise of computers and AI. This work seemed to show that some aspects of cognition are mechanizable in principle, and in a non-living system. There's no question of life being present in a classical AI system, or a familiar sort of robot, and given that there seems a real possibility that such a system might capture of all of mentality, there can't apparently be too close a link between life and mind. Computation, rather than life, became the crucial bridging concept between mental and physical.
That's what Dennett thought. But he's now, sorta, realized that we've got to have life in there. PGS on "matter at the scale of metabolism" (p. 4):
Metabolic processes in actual cells occur at a particular spatial scale, the scale measured in nanometers – millionths of a millimeter. They also take place in a particular context, surrounded by water. In that context and at that scale, matter behaves differently from how it behaves elsewhere. In a phrase due to Hoffman, what we find is a molecular storm. There is unending spontaneous motion, which does not need to be powered by anything external. Larger molecules rearrange themselves spontaneously and vibrate, and everything is bombarded by water molecules, with the larger molecules being hit by a water molecule trillions of times per second. Electical charge also plays a ubiquitous role, through ions dissolved in the water and charged regions of larger molecules. The parts of a cell that do things in the usual sense – making proteins, for example – are subject to forces that are much stronger than the forces they can exert. The way things get done is by biasing tendencies in the storm, nudging random walks in useful directions, thereby getting a consistent upshot out of vast numbers of mostly meaningless changes. Moore, though not Hoffman, thinks we should conclude from all this that "Macromolecular Devices Are Not Machines." Moore thinks that a machine is a quite definite sort of thing, where low-level interactions are predictable and parts are tightly coupled. A storm-like collection of random walks influenced by friction, charge, and thermal effects, in contrast, is non-mechanistic.

















