Mohammed Must Go To The Mountain
Leibniz raised a knotty problem with the dynamics of perception that may at last have some sort of solution. As Descartes had done, he argued that a subject of experience could not have parts, each of which received some of the signals that were to mediate perception. The entire subject must receive all the signals. The only way this would seem to be possible on a naïve view of dynamics would be if the subject was at a single point in space and the signals came in from different angles, like light rays, so that their pattern could signify what was to be perceived.
The difficulty with this is that physics has built up an account in which the effects of the world on any dynamic unit are mediated through potentials, and there is only one potential of any one type at any place. Whether or not one sees this in terms of ‘forces’ it seems that a point-like subject in one place would have a very limited account of the world available. The trouble is that if the subject is not point-like then it would seem that only part of it would have access to potentials on the left hand side and another part to potentials on the right hand side and so on.
This approach might be seen as ‘the mountain coming to Mohammed’. It fits with the popular view that we can just sit in a chair and drink in the signals coming to us from the Matterhorn or Jungfraujoch in the distance. It fits with the idea that the final step in perception is essentially passive, even if it feeds off ‘feeling around’ calibrating manoevres by our bodies in some cases.
Leibniz does not, as far as I know, untie this knot, but his approach provides an important clue to how it might be done. For Leibniz each individual subject or monadic entity is a dynamic unit. Its nature is purely to perceive and to progress in harmony with the universe it perceives. It has an inner ‘entelechy’ (like the tension in a bow string) that drives it constantly forward in time. The logical corollary to this is that we should think of the subject as constantly moving. Constant motion would solve our problem by ‘Mohammed going to the mountain’ in the sense of the subject visiting a rich pattern of potentials spread out over space and time. Yet it seems as if structures in the brain stay still.
This is where I think modern physics may help us. The bits of modern physics relevant to everyday life are mostly dynamic units like electrons that according to theory are undergoing constant change, progressing through space and time, but more often than not in a way such that they stay in the same place, like standing waves or spinning tops. The free electrons in an electrically conducting metal spoon range throughout the whole spoon but in such a way that whenever you study them they seem to be the same. Electrons may not be very good candidates for human subjects, for technical reasons, but the general principle provides a chink of light in an otherwise dark area.