incommensurability of rhythm; and we may surmise that the same thing is true of the corresponding psychic minor systems in consciousness which in like manner may be said to be incommensurable.
We have thus a very simple explanation of such facts as the familiar one that the soldier in the wild excitement of battle does not note the painful sensations of the wound in his leg. The brain consciousness is then so intensely active in its relation to the mental states initiated by his sensations of sight and hearing, that these activities are incommensurable with those in the less active minor psychic systems affected by the wound.
But especially does this conception throw light, in cases of socalled 'double personality' upon the failure of recall by the one personality, of the occurrences in the conscious life of the other personality; and also of the failure of recall by the hypnotic patient, in his normal life, of his mental states during his trance. Here we may assume that two diverse great minor psychic systems, which are utterly incommensurable in rhythm, alternately take possession, as it were, of the body of man, and control his expressions. Being thus incommensurable, the two systems are almost exactly as much disconnected as are two individual men, and of course under such circumstances the mental states of one psychic system can not in any way be revived in the conscious life of the other psychic system.
We may now turn to another important point. "We have stepped from the complex fully developed human consciousness to the simpler consciousnesses of the animals. We have further seen that under certain conditions there may be in our own bodies simpler consciousnesses than what we may call, for the sake of brevity, the 'brain consciousness.' But can we not—in fact, ought we not—take a further step, and hold that psychic elements may exist?
Apparently, if we are to be logical, we must take this step. We must assume that if we could isolate a neural element, a psychic element would correspond with its activities. It is true that the neurologist has never been able to discover a disconnected, isolated, living neural element; and it is true also that we can not isolate any psychic element, and even if we could do so, it as an element could not be emphatic in consciousness which is necessarily systemic and not elemental.
But now we may note that if disconnected minor neural systems may exist in our animal body there seems to be no reason why living neural elements may not from time to time become disconnected from, and then again reconnected with, one or another minor nervous system: and correspondingly no reason why psychic elements may not from time to time be disconnected from, and then reconnected with, one
