This is a kind of dream which has occurred in all ages, and has at times been put down to divine interposition. Sixteen centuries ago Bishop Synesius of Ptolemais wrote that in his hunting days a dream revealed to him an idea for a trap which he successfully employed in snaring animals, and at the present time inventions made in dreams have been successfully patented. The Rev. Nehemiah Curnock, who lately succeeded in deciphering Wesley's Journal, has stated that an important missing clue to the cypher came to him in a dream. A friend of my own, an expert in chemistry, was not long since in frequent communication with a practical manufacturer, assisting him in his inventions by scientific advice. One day the manufacturer wrote to my friend asking if the latter had been thinking of him during the night, for he had been much puzzled by a difficulty, and during the night had seen a vision of my friend who explained the solution of the difficulty; in the morning the proposed solution proved successful. There was, however, no telepathic element in the case; the dreamer's solution was his own.

An interesting group of cases in this class is furnished by the dreams in which the dreamer, in opposition to his waking judgment, sees an acquaintance in whom he reposes trust acting in a manner unworthy of that trust, subsequent events proving that the estimate formed during sleep was sounder than that of waking life. Hawthorne (in his American Notebooks), Greenwood, Jewell, and others have recorded cases of this kind.

Various as these phenomena are, they fall into the same scheme. They all help to illustrate the fact that though on one side mental life in sleep is feeble and defective, on the other side it shows a tendency to vigorous excess. Sleep, as we know, involves a relaxation of tension, both physical and psychic; attention is no longer focused at a deliberately selected spot.[207] The voluntary field becomes narrower, but the involuntary field becomes extended. Thus it happens that the contents of our minds fall into a new order, an order which is often fantastic but, on the other hand, is sometimes a more natural and even a more rational order than that we attain in waking life. Our eyes close, our muscles grow slack, the reins fall from our hands. But it sometimes happens that the horse knows the road home even better than we know it ourselves.

Hypermnesia, or abnormally wide range of recollection, is not the only or the most common modification of memory during sleep. We find much more commonly, and indeed as one of the chief characteristics of sleep, an abnormally narrow range of recollection. We find, also, and perhaps as a result of that narrow range, paramnesia or perversion of memory. The best known form of paramnesia is that in which we have the illusion that the event which is at the moment happening to us has happened to us before.[208]

This form of paramnesia is common in dreams, though it is often so slightly pronounced that we either fail to recall it on awakening or attach no significance to it.[209] I dream, for instance, that I am walking along a path, along which, it seems to me, I have often walked before, and that the path skirts the lawn of a house by which stands a policeman whom, also, it seems to me, I have often seen there before; the policeman approaches me and says, 'You have come to see Mr. So-and-so, sir?' and thereupon I suddenly recollect, with some confusion, that I have come to see Mr. So-and-so, and I walk up to the door. Again, an author dreams that he sees a list of his own books with, at the head of them, one entitled 'The Book of Glory.' He could not recall writing it (and to waking consciousness the name was entirely unknown), but the only reflection he made in his dream was 'How stupid to have forgotten!' In this case there was evidently some resistance to the suggestion, which yet was quickly accepted. In all such dreams it seems that we are in a state of mental weakness associated with defective apperceptual control and undue suggestibility, very similar to the state found in some forms of confusional insanity or of precocious dementia.[210] Consciousness feebly slides down the path of least resistance; it accepts every suggestion; the objects presented to it seem things that it knew before, the things that are suggested to it to do seem things that it already wanted to do before. Paramnesia, thus regarded, seems simply a natural outcome of a state of consciousness temporarily depressed below its normal standard of vigour.

It must be remembered that the suggestibility of sleeping consciousness varies in degree, and in the face of serious improbabilities there is often a considerable amount of resistance, just as the hypnotised person seriously resists the suggestions that fundamentally outrage his nature. But some degree of suggestibility, some tendency to regard the things that come before us in dreams as familiar—in other words, as things that have happened to us before—is not merely a natural result of defective apperception, but one of the very conditions of dreaming. It enables us to carry on our dreams; without it their progress would be fatally inhibited by doubt, uncertainty, and struggle. So it is, perhaps, that in all dreaming, or at all events in certain stages of sleeping consciousness, we are liable to fall into a state of pseudo-reminiscence.

It is an interesting and highly significant fact that this paramnesic delusion of our dreams—the feeling that the thing that is happening to us is the thing that has happened to us before or that might happen to us again—tends to persist in the hypnagogic (or hypnopompic) stage immediately following sleep. When we have half awakened from a dream and are just able to realise that it was a dream, that dream constantly tends to appear in a more plausible or probable light than is possible a few moments later when we are fully awake.[211]

The first experience which enabled me clearly to realise this phenomenon, and its probable explanation, occurred many years ago. About the middle of the night I had a very vivid dream, in which I imagined that two friends—a gentleman and his daughter—with a certain Lord Chesterfield (I had lately been reading the Letters of the famous Lord Chesterfield), were together at a hotel, that they were playing with weapons, that the lady accidentally killed or wounded Lord Chesterfield, and that she then changed clothes with him with the object of escaping, and avoiding discovery which would somehow be dangerous. I was informed of the matter, and was much concerned. I awoke, and my first thought was that I had just had a curious dream which I must not forget in the morning. But then I seemed to remember that it was a real and familiar event. This second thought lulled my mental activity, and I went to sleep again. In the morning I was able to recall the main points in my dream, and my thoughts on awaking from it.

Since then I have given attention to the point, and I have found on recalling my half-waking consciousness after dreams that, while it is doubtless rare to catch the assertion 'That really occurred,' it is less rare to catch the vague assertion, 'That is the kind of thing that does occur.' I find that this latter impression appears, like the former, after vivid dreams which contain no physical impossibility, but which the full waking consciousness refuses to recognise as among the things that are probable. As an example quite unlike that just recorded, I may mention a dream in which I imagined that I was proving the frequency of local intermarriage by noting in directories the frequency of the presence of people of the same name in neighbouring towns and villages. On half-awaking I still believed that I had actually been engaged in such a task—that is, either that the dream was real or that it referred to a real event—and it was not until I was sufficiently awake to recognise the fallacy of such a method of investigation that I realised that it was purely a dream.

This phenomenon has long been known, although its significance has not been perceived. Brierre de Boismont pointed out that certain vivid dreams are not recognised as dreams, but are mistaken for reality after waking, though he scarcely recognised the normal limitation of this mistake to the hypnagogic state. Moll compared such dreams, thus continued into waking life, to continuative post-hypnotic suggestions. Sully mentioned awaking from dreams which 'still wear the aspect of old acquaintances, so that for the moment I think they are waking realities.'[212] Colegrove, in his study of memory, recorded many cases in which young people mistook their dreams for actual events.[213]