Except for the aforesaid arbitrary limitation, the collecting of material lies outside the investigator's discretion. The material gathered must now be sifted and examined, according to principles which are always applied to the examination of historical or any empirical scientific material. The method is an essentially comparative one, that obviously cannot be applied automatically, but is largely dependent upon the skill and aim of the investigator.

When a psychological fact has to be explained, it must be remembered that psychological data necessitate a twofold point of view, namely, that of causality and that of finality. I use the word finality intentionally, in order to avoid confusion with the idea of "teleology." I use finality to denote immanent psychological teleology. In so far as we apply the view point of causality to the material that has been associated with the dream, we reduce the manifest dream content to certain fundamental tendencies or ideas. These, as one would expect, are elementary and universal in character.

For instance, a young patient dreams as follows: "I am standing in a strange garden, and pluck an apple from a tree. I look about cautiously, to make sure no one sees me."

The associated dream material is a memory of having once, when a boy, plucked a couple of pears surreptitiously from another person's garden.

The feeling of having a bad conscience, which is a prominent feature in the dream, reminds him of a situation he experienced on the previous day. He met a young lady in the street—a casual acquaintance—and exchanged a few words with her. At that moment a gentleman passed whom he knew, whereupon our patient was suddenly seized with a curious feeling of embarrassment, as if he had done something wrong. He associated the apple with the scene in Paradise, together with the fact that he had never really understood why the eating of the forbidden fruit should have been fraught with such dire consequences for our first parents. This had always made him feel angry; it seemed to him an unjust act of God, for God had made men as they were, with all their curiosity and greed.

Another association was, that sometimes his father had punished him for certain things in a way that seemed to him incomprehensible. The worst punishment had been bestowed after he had secretly watched girls bathing.

That led up to the confession that he had recently begun a love affair with a housemaid, but had not yet carried it through to a conclusion. On the day before the dream he had had a rendezvous with her.

Upon reviewing this material we see that the dream contains a very transparent reference to the last-named incident. The connecting associative material shows that the apple episode is palpably meant for an erotic scene. For various other reasons, too, it may be considered extremely probable that this experience of the previous day is operative even in this dream. In the dream the young man plucks the apple of Paradise, which in reality he has not yet plucked. The remainder of the material associated with the dream is concerned with another experience of the previous day, namely, with the peculiar feeling of a bad conscience, which seized the dreamer when he was talking to his casual lady acquaintance; this, again, was connected with the fall of man in Paradise, and finally with an erotic misdemeanour of his childhood, for which his father had punished him severely. All these associations are linked together by the idea of guilt.