Even so, the relation between the soul and the gland was absolutely unintelligible, as Descartes disarmingly confessed.  Incarnation was all very well in the old philosophy:  those who had allowed the interaction of disparate natures throughout the physical world need find no particular difficulty about the special case of it provided by incarnation.  Why should not a form of conscious life so interact with what would otherwise be dead matter as to ‘indwell’ it?  But the very principle of the new philosophy disallowed the interaction of disparate natures, because such an interaction did not allow of exact formulation, it was a ‘loose’ and not a ‘tight’ relation.

From a purely practical point of view the much derided pineal gland theory would serve.  If we could be content to view Descartes as a man who wanted to make the world safe for physical science, then there would be a good deal to be said for his doctrine.  In the old philosophy exact science had been frustrated by the hypothesis of loose relations all over the field of nature.  Descartes had cleared them from as much of the field as science was then in a position to investigate; he allowed only one such relation to subsist, the one which experience appeared unmistakably to force upon us—­that between our own mind and its bodily vehicle.  He had exorcized the spirits from the rest of nature; and though there was a spirit here which could not be exorcized, the philosophic conjurer had nevertheless confined it and its unaccountable pranks within a minutely narrow magic circle:  all mind could do was to turn the one tiny switch at the centre of its [20] animal telephone system.  It could create no energy—­it could merely redirect the currents actually flowing.

Practically this might do, but speculatively it was most disturbing.  For if the ‘loose relation’ had to be admitted in one instance, it was admitted in principle; and one could not get rid of the suspicion that it would turn up elsewhere, and that the banishment of it from every other field represented a convenient pragmatic postulate rather than a solid metaphysical truth.  Moreover, the correlation of the unitary soul with the unitary gland might do justice to a mechanistical philosophy, but it did not do justice to the soul’s own consciousness of itself.  The soul’s consciousness is the ‘idea’ or ‘representation’ of the life of the whole body, certainly not of the life of the pineal gland nor, as the unreflective nowadays would say, of the brain.  I am not conscious in, or of, my brain except when I have a headache; consciousness is in my eyes and finger-tips and so on.  It is physically true, no doubt, that consciousness in and of my finger-tips is not possible without the functioning of my brain; but that is a poor reason for locating the consciousness in the brain.  The filament of the electric bulb will not be incandescent apart from the functioning of the dynamo; but that is a poor reason for saying that the incandescence is in the dynamo.