It would also account for those dreams in which the dreamer perceives an incident at a distance which is subsequently verified.
As for the ordinary chaotic dream, this, it seems to me may be accounted for in either of two main ways. If we suppose that the stimulation of certain cells (memory centres) in the brain causes an uprush into consciousness of the associated item of memory or "souvenir," it is not unreasonable to suppose that such stimulation is going on in the body all the time. But it will only be in the state, intermediate between profound sleep and waking, that these aroused souvenirs will, on the one hand get through to the consciousness—which in deep sleep is separated from the body altogether—and, on the other will escape over-ruling by the Will or obliteration by the influx of normal sensory impressions.
This would account for the fact that the majority of dreams appear to be of very short duration and to take place in the very act of waking.
The other cause of ordinary dreams is probably in its general nature suggestive. That is to say the Ego cut off from the outside world by the imperfections of its four-dimensional senses is quiescent, and in a state peculiarly favourable for the telepathic picking up of stray thoughts which suggest dreams.
This of course is especially the case when the dream is deliberately suggested by a hypnotic specialist, as is sometimes done.[2]
The subject of Phantasmal apparitions is also both complex in its varieties and obscure as to its causes.
The commonest explanation, namely, the telepathic influence of the percipient by the agent, does not seem to me to be applicable to every case. For instance, it is difficult to conceive how a man shot through the head can visualise himself sufficiently clearly at that moment to project a telepathic image of himself, including the wound, to the percipient. And, more generally, it is probable that few of us could visualise our own appearance with sufficient accuracy to do more than convey, telepathically, a vague general impression. On the other hand, if we are to suppose that the details are filled up, so to speak, by the percipient, how are we to explain accurate perception of clothing and so forth of which the percipient could have no knowledge?
Finally, the whole telepathic theory seems weak in this respect. If I in the act of death, vehemently long for, or think of, a certain person, it is clear that the thought in my mind which is most likely to be transmitted to the brain of a percipient will not be the thought of myself—still less of my own appearance—but rather of the other person. Why should this suggest me to his mind?
In experimental telepathy it is the idea on which the agent concentrated his mind that is transmitted to the percipient, not some other idea, and I see no reason for supposing that this is not always the case.