No deep insight into mental mechanisms is possible without taking cognizance of the fact of two kinds of thinking: one variously designated logical, directed, or realistic, the other dream, phantasy, or autistic thinking. "The first, working for communication with speech elements, is troublesome and exhausting; the latter, on the contrary, goes on without trouble, working spontaneously, so to speak, with reminiscences. The first creates innovations, adaptations, imitates reality and seeks to act upon it. The latter, on the contrary, turns away from reality, sets free subjective wishes, and is, in regard to adaptation, wholly unproductive." !

"In general, a tendency to realistic, ' logical,' 'common-sense' thinking grows in us by reason of its service in meeting our situations favorably and wholesomely. Just as useful patterns of behavior tend to be perpetuated, and harmful ones to disappear by selection, so have the modes of thought that are more useful tended more and more to order our important actions. Almost the entire thinking of primitive humanity was governed by indiscriminate, simply associative modes of thought, not yet subjected to the selective test of 'working' or failure. Autistic thinking in relation to the sphere of voluntary conduct is therefore very prominent in them. Such thinking appears in the foreground of mental disease as we see it to-day. But in normal persons, autistic thinking is gradually being relegated to less essential functions, like dreaming, wit, and forms of mental recreation. In the mentally healthier persons, this relegation and selection is the more complete. Realistic and directive thinking has been more and more selected for survival." 1

1C. G. Jung. Psychology of the Unconscious. English Translation by Beatrice M. Hinkle. New York, 1916.

"The element of the dream thoughts which I have in mind, I am in the habit of designating as a ' phantasy'; perhaps I shall avoid misunderstanding if I immediately adduce the day dream of waking life as an analogy." "A more thorough examination into the character of these day phantasies shows with what good reason the same name has been given to these formations as to the products of our nocturnal thoughts - dreams." "Like dreams, they are fulfilments of wishes; like dreams, a good part of them are based upon the impressions of childish experiences; like dreams their creations enjoy a certain amount of indulgence from the censor." The sleeping dream, however, is distinguished from the day dream in that "the presentation content is not thought, but changed into perceptible images to which we give credence and which we believe we experience." 2

"The boundary line between rational and autistic speculations cannot be laid down by human intellect. What is inconceivable to-day may to-morrow become fact; what is firmly believed to-day may to-morrow become false.

1 F. L. Wells. Mental Adjustments. New York, 1917.

2 S. Freud. The Interpretation of Dreams. English translation by A. A. Brill. New York, 1916.

Therefore a humanity without autistic thinking could not have been developed. But autistic thinking being once there, it will be used, whensoever convenient, whether useful or not. Now conceptions are pleasant or unpleasant just as well as outer experiences. One can therefore give pleasure to oneself by dwelling on pleasant ideas. But the animal organism is from phylogenetically ancient times adapted to seek pleasure and to avoid pain. In the outer world the pleasure- and pain-provoking events are such that this reaction upon them corresponds in general to our needs. But in pure imagination at once a new field of unlimited possibilities unfolds itself. Therein is the danger for man and at the same time his advantage over the brutes. The health of the individual and of nations demands a balanced proportion of autistic and realistic function. The realistic must control the autistic. But the autistic contains most of our ideals. Let us take care to keep them on the same level as our technical progress and not to misuse them to harass and to destroy our neighbors." 1