In spite of the fact that for centuries endeavours have been made to extract a prophetic meaning from dreams, Freud's discovery is practically the first successful attempt to find their real significance. His work merits the term "scientific," because he has evolved a technique which, not only he, but many other investigators also assert achieves its object, namely, the understanding of the meaning of the dream. This meaning is not identical with the one which the manifest dream content seems to indicate.

This is not the place for a critical discussion of Freud's psychology of dreams. But I will try to give a brief summary of what may be regarded as more or less established facts of dream psychology to-day.

The first question we must discuss is, whence do we deduce the justification for attributing to dreams any other significance than the one indicated in the unsatisfying fragmentary meaning of the manifest dream content?

As regards this point a particularly weighty argument is the fact that Freud discovered the hidden meaning of dreams by empiric and not deductive methods. A further argument in favour of a possible hidden, as opposed to the manifest meaning of dreams, is obtained by comparing dream-phantasies with other phantasies (day-dreams and the like) in one and the same individual. It is not difficult to conceive that such day-phantasies have not merely a superficial, concrete meaning, but also a deeper psychological meaning. It is solely on account of the brevity that I must impose upon myself, that I do not submit materials in proof of this. But I should like to point out that what may be said about the meaning of phantasies, is well illustrated by an old and widely diffused type of imaginative story, of which Æsop's Fables are typical examples, wherein, for instance, the story is some objectively impossible phantasy about the deeds of a lion and an ass. The concrete superficial meaning of the fable is an impossible phantasm, but the hidden moral meaning is plain upon reflection. It is characteristic that children are pleased and satisfied with the exoteric meaning of the story. However, the best argument for the existence of a hidden meaning in dreams is provided by conscientious application of the technical procedure to solve the manifest dream content.

This brings us to our second main point, viz.—the question of analytic procedure. Here again I desire neither to defend nor to criticise Freud's views and discoveries, but rather to confine myself to what seem to me to be firmly established facts.

The fact that a dream is a psychic structure, does not give us the slightest ground for assuming that it obeys laws and designs other than those applicable to any other psychic structure. According to the maxim: principia explicandi prœter necessitatem non sunt multiplicanda, we have to treat dreams, in analysis, just as any other psychic structure, until experience teaches us some better way.

We know that every psychic construction considered from the standpoint of causality, is the resultant of previous psychic contents. Moreover, we know also that every psychic structure, considered from the standpoint of finality, has its own peculiar meaning and purpose in the actual psychic process. This standard must also be applied to dreams. When, therefore, we seek a psychological explanation of a dream, we must first know what were the preceding experiences out of which it is combined. We must trace the antecedents of every element in the dream picture. For example: some one dreams "that he is walking in a street, a child is running in front of him, who is suddenly run over by a motor-car." We will trace the antecedents of this dream-picture, with the aid of the dreamer's recollections.

He recognises the street as one down which he had walked on the previous day. The child he acknowledges as his brother's child, whom he had seen on the previous evening when visiting his brother. The motor accident reminds him of an accident that had actually occurred a few days before, but of which he had only read an account in a newspaper. Popular opinion is known to be satisfied with this kind of explanation. People say: "Oh, that is why I dreamt such and such a thing!"

Obviously this explanation is absolutely unsatisfactory from a scientific standpoint. The dreamer walked down many streets on the previous day; why was this particular one selected? He had read about several accidents; why did he select just this one? The mere disclosure of an antecedent is by no means sufficient; for a plausible determination of the dream presentation can only be obtained from the competition of various determinants. The collection of additional material proceeds, according to the principle of recollection that has been called the Association Method. The result, as will easily be understood, is the admission of a mass of multifarious and quite heterogeneous material, having apparently nothing in common but the fact of its evident associative connection with the dream contents, since it has been reproduced by means of this content.

How far the collection of such material should go, is an important question from the technical point of view. Since the entire psychic content of a life may be ultimately disclosed from any single starting point, theoretically the whole previous life-experience might be found in every dream. But we only need to assemble just so much material as is absolutely necessary in order to comprehend the dream's meaning. The limitation of the material is obviously an arbitrary proceeding, according to that principle of Kant's whereby to comprehend is "to perceive to the extent necessary for our purpose." For instance, when undertaking a survey of the causes of the French Revolution, we could, in amassing our material, include not only the history of medieval France but also that of Rome and Greece, which certainly would not be "necessary for our purpose," since we can comprehend the historical genesis of the Revolution from much more limited material.