879. As has been usual in this inquiry, this slight forward step from vagueness to comparative clearness of conception introduces us at once to a whole series of novel problems. Yet, as we have also learnt to expect, some of our earlier phenomena may have to be called in with advantage to illustrate phenomena more advanced.

In cases of split personality, to begin with, we have seen just the same phenomena occurring where certainly no personality was concerned save the percipient's own. We have seen a section of the subliminal self partially or temporarily dominating the organism; perhaps (as in Anna Winsor's case, 237 A) controlling permanently one arm alone; or perhaps controlling intermittently the whole nervous system; - and all this with varying degrees of displacement of the primary personality.

Similarly with post-hypnotic suggestion. We have seen the subliminal self ordered to write (say) "It has left off raining" - and thereupon writing the words without the conscious will of the automatist - and again with varying degrees of displacement of the waking self. The step hence to such a case as Mrs. Newnham's (849 A) is thus not a very long one. Mrs. Newnham's subliminal self, exercising supernormal faculty, and by some effort of its own, acquires certain facts from Mr. Newnham's mind, and uses her hand to write them down automatically. The great problem here introduced is how the subliminal self acquires the facts, rather than how it succeeds in writing them down when it has once acquired them.

But as we go further we can no longer limit the problem in this way, - to the activities of the automatist's subliminal self. We cannot always assume that some portion of the automatist's personality gets at the supernormal knowledge by some effort of its own. Our evidence, as we know, has pointed decisively to telepathic impacts or influences from without. In the Kirby case (852), for instance, we have supposed that the spirit of the sleeping sister affected the brother by a telepathic impact, from without, which worked itself out by automatic movements just like those automatic movements which we have already described as originating wholly from within. What, then, is the mechanism here? Are we still to suppose that the automatist's subliminal self executes the movements - obeying somehow the bidding of the impulse from without? or does the external agent, who sends the telepathic message, himself execute the movements also, directly using the automatist's arm? And if telekinetic movements accompany the message, (a subject thus far deferred, but of prime importance), are we to suppose that these also are effected by the percipient's subliminal self, under the guidance of some external spirit, incarnate or discarnate? or are they effected directly by that external spirit?

880. We cannot really say which of these two is the easier hypothesis.

From one point of view it may seem simpler to keep as long as we can to that acknowledged vera causa, the automatist's subliminal self; and to collect such observations as may indicate any power on its part of producing physical effects outside the organism. Such scattered observations occur at every stage, and even Mrs. Newnham, (I may briefly observe in passing), thought that her pencil, when writing down the messages tele-pathically derived from her husband, was moved by something other than the ordinary muscular action of the fingers which held it. On the other hand, there seems something very forced in attributing to an external spirit's agency impulses and impressions which seem intimately the automatist's own, and at the same time refusing to ascribe to that external agency phenomena which take place outside the automatist's organism, and which present themselves to him as objective facts, as much outside his own being as the fall of the apple to the ground.

Reflecting on such points - and once admitting this kind of interaction between the automatist's own spirit and an external spirit, incarnate or discarnate - we find the possible combinations presenting themselves in perplexing variety; - a variety both of agencies on the part of the invading spirit, and of effects on the part of the invaded spirit and organism.

What is that which invades? and what is that which is displaced or superseded by this invasion? In what ways may two spirits co-operate in the possession and control of the same organism?

These last words - control and possession - remind us of the great mass of vague tradition and belief to the effect that spirits of the departed may exercise such possession or control over the living. To those ancient and vague beliefs it will be our task in the next chapter to give a form as exact and stable as we can. And observe with how entirely novel a preparation of mind we now enter on that task. The examination of "possession" is no longer to us, as to the ordinary civilised inquirer, a merely antiquarian or anthropological research into forms of superstition lying wholly apart from any valid or systematic thought. On the contrary, it is an inquiry directly growing out of previous evidence; directly needed for the full comprehension of known facts as well as for the discovery of facts unknown. We need (so to say), to analyse the spectrum of helium, as detected in the sun, in order to check and correct our spectrum of helium as detected in the Bath waters. We are obliged to seek for certain definite phenomena in the spiritual world in order to explain certain definite phenomena of the world of matter.