As has been said, those writers of antiquity who preceded Aristotle did not regard the dream as a product of the dreaming psyche, but as an inspiration of divine origin, and in ancient times the two opposing tendencies which we shall find throughout the ages in respect of the evaluation of the dream- life were already perceptible. The ancients distinguished between the true and valuable dreams which were sent to the dreamer as warnings, or to foretell future events, and the vain, fraudulent, and empty dreams whose object was to misguide him or lead him to destruction.

Gruppe * speaks of such a classification of dreams, citing Macrobius and Artemidorus: "Dreams were divided into two classes; the first class was believed to be influenced only by the present (or the past), and was unimportant in respect of the future; it included the enuknia (insomnia), which directly reproduce a given idea or its opposite; e.g., hunger or its satiation; and the phantasmata, which elaborate the given idea phantastically, as e.g. the nightmare, ephialtes. The second class of dreams, on the other hand, was determinative of the future. To this belonged:

1. Direct prophecies received in the dream (chrematismos, oraculum);

2. the foretelling of a future event (orama, visio);

3. the symbolic dream, which requires interpretation (oneiros, somnium.)

This theory survived for many centuries."

* Griechische Mythologie und Religionsgeschichte, p. 390.

Connected with these varying estimations of the dream was the problem of "dream-interpretation." Dreams in general were expected to yield important solutions, but not every dream was immediately understood, and it was impossible to be sure that a certain incomprehensible dream did not really foretell something of importance, so that an effort was made to replace the incomprehensible content of the dream by something that should be at once comprehensible and significant. In later antiquity Artemidorus of Daldis was regarded as the greatest authority on dream-interpretation. His comprehensive works must serve to compensate us for the lost works of a similar nature. * The pre-scientific conception of the dream which obtained among the ancients was, of course, in perfect keeping with their general conception of the universe, which was accustomed to project as an external reality that which possessed reality only in the life of the psyche. Further, it accounted for the main impression made upon the waking life by the morning memory of the dream; for in this memory the dream, as compared with the rest of the psychic content, seems to be something alien, coming, as it were, from another world. It would be an error to suppose that theory of the supernatural origin of dreams lacks followers even in our own times; for quite apart from pietistic and mystical writers- who cling, as they are perfectly justified in doing, to the remnants of the once predominant realm of the supernatural until these remnants have been swept away by scientific explanation- we not infrequently find that quite intelligent persons, who in other respects are averse from anything of a romantic nature, go so far as to base their religious belief in the existence and co- operation of superhuman spiritual powers on the inexplicable nature of the phenomena of dreams (Haffner). The validity ascribed to the dream-life by certain schools of philosophy- for example, by the school of Schelling- is a distinct reminiscence of the undisputed belief in the divinity of dreams which prevailed in antiquity; and for some thinkers the mantic or prophetic power of dreams is still a subject of debate. This is due to the fact that the explanations attempted by psychology are too inadequate to cope with the accumulated material, however strongly the scientific thinker may feel that such superstitious doctrines should be repudiated.

* For the later history of dream-interpretation in the Middle Ages consult Diepgen, and the special investigations of M. Forster, Gotthard, and others. The interpretation of dreams among the Jews has been studied by Amoli, Amram, and Lowinger, and recently, with reference to the psycho- analytic standpoint, by Lauer. Details of the Arabic methods of dream- interpretation are furnished by Drexl, F. Schwarz, and the missionary Tfinkdji. The interpretation of dreams among the Japanese has been investigated by Miura and Iwaya, among the Chinese by Secker, and among the Indians by Negelein.