In agreement with my honoured collaborator, Dr. C. E. Long, I have made certain additions to the second edition. It should especially be mentioned that a new chapter upon "The Concept of the Unconscious" has been added. This is a lecture I gave early in 1916 before the ZÜrich Union for Analytical Psychology. It gives a general orientation of a most important problem in practical analysis, viz. of the relation of the psychological ego to the psychological non-ego. Chapter XIV. has been fundamentally altered, and I have used the opportunity to incorporate an article that should describe the results of more recent researches. In accordance with my usual mode of working, the description is as generalised as possible. My habit in my daily practical work is to confine myself for some time to studying my human material. I then abstract as generalised a formula as possible from the data collected, obtaining from it a point of view and applying it in my practical work, until it has either been confirmed, modified, or else abandoned. If it has been confirmed, I publish it as a general view-point, without giving the empirical material. I only introduce the material amassed in the course of my practice in the form of example or illustration. I therefore beg the reader not to consider the views I present as mere fabrications of my brain. They are, as a matter of fact, the results of extensive experience and ripe reflection.

These additions will enable the reader of the second edition to become familiar with the recent views of the ZÜrich School.

As regards the criticism encountered by the first edition of this work, I was pleased to find my writings were received with much more open-mindedness among English critics than was the case in Germany, where they are met with the silence born of contempt. I am particularly grateful to Dr. Agnes Savill for an exceptionally understanding criticism in the Medical Press. My thanks are also due to Dr. T. W. Mitchell for an exhaustive review in the Proceedings of the Society for Psychical Research. This critic takes exception to my heresy respecting causality. He considers that I am entering upon a perilous, because unscientific, course, when I question the sole validity of the causal view-point in psychology. I sympathise with him, but in my opinion the nature of the human mind compels us to take the final point of view. For it cannot be disputed that, psychologically speaking, we are living and working, day by day, according to the principle of directed aim or purpose, as well as that of causality. A psychological theory must necessarily adapt itself to this fact. What is plainly directed towards a goal cannot be given an exclusively causalistic explanation, otherwise we should be led to the conclusion expressed in Moleschott's famous enunciation: "Man is, what he eats." We must always bear the fact in mind that causality is a point of view. It affirms the inevitable and immutable relation of a series of events: a-b-d-z. Since this relation is fixed, and according to the view-point must necessarily be so, looked at logically the order may also be reversed. Finality is also a view-point, that is justified empirically solely by the existence of series of events, wherein the causal connection is indeed evident, but the meaning of which only becomes intelligible as producing final effect. Ordinary daily life furnishes the best instances of this. The causal explanation must be mechanistic, if we are not to postulate a metaphysical entity as first cause. For instance, if we adopt Freud's sexual theory and assign primary importance psychologically to the function of the genital glands, the brain is viewed as an appendage of the genital glands. If we approach the Viennese idea of sexuality with all its vague omnipotence, and trace it in a strictly scientific manner down to its psychological basis, we shall arrive at the first cause, according to which psychic life is for the most, or the most important part, tension and relaxation of the genital glands. If we assume for the moment that this mechanistic explanation be "true," it would be the sort of truth which is exceptionally tiresome and rigidly limited in scope. A similar statement would be that the genital glands cannot function without adequate nourishment, with its inference that sexuality is an appendage-function of nutrition! The truth contained in this is really an important chapter in the biology of lower forms of life.

But if we wish to work in a really psychological way, we shall want to know the meaning of psychological phenomena. After learning the kinds of steel the various parts of a locomotive are made of, and from what ironworks and mines they come, we do not really know anything about the locomotive's function, that is to say, its meaning. But "function" as conceived by modern science is by no means solely a causal concept; it is especially a final or "teleological" one. For it is utterly impossible to consider the soul from the causal view-point only; we are obliged to consider it also from the final point of view. As Dr. Mitchell also points out, it is impossible for us to think of the causal determination conjointly with a final connection. That would be an obvious contradiction. But our theory of cognition does not need to remain on a pre-Kantian level. It is well known that Kant showed very clearly that the mechanistic and the teleological view-points are not constituent (objective) principles, in some degree qualities of the object, but that they are purely regulative (subjective) principles of thought, and as such they are not mutually inconsistent. I can, for example, easily conceive the following thesis and antithesis:—

Thesis: Everything came into existence according to mechanistic laws.

Antithesis: Some things did not come into existence according to mechanistic laws only.

Kant says to this: Reason cannot prove either of these principles, because a priori purely empirical laws of nature cannot give us a determinative principle regarding the potentiality of things.

As a matter of fact, modern physics has necessarily been converted from the idea of pure mechanism to the final concept of the conservation of energy, because the mechanistic explanation only recognises reversible processes, whereas the actual truth is that the process of nature is irreversible. This fact led to the concept of an energy that tends towards relief of tension, and therewith also towards a definite final state.

Obviously, I consider both these points of view necessary, the causal as well as the final, but would at the same time lay stress upon the fact that since Kant's time we have come to know that the two view-points are not antagonistic if they are regarded as regulative principles of thought, and not as constituent principles of the process of nature itself.

When speaking of the reviews, I must also mention those that seem to me beside the mark. I was once more struck by the fact that certain critics cannot distinguish between the theoretical explanation given by the author, and the phantastic ideas provided by the patient. One of my critics makes this confusion when discussing "Number Dreams." The associations to the quotation from the Bible in Chapter V. are, as every attentive reader must readily perceive, not arbitrary explanations of my own, but a cryptomnesic conglomeration emanating, not from my brain at all, but from that of the patient. Surely it is not difficult to perceive upon reflection that this conglomeration of numbers corresponds exactly to that unconscious psychological function from which proceeded all the mysticism of numbers, Pythagoric, Kabbalistic, and so forth, existent from untold ages.

I am grateful to my serious reviewers, and should like here to also express my thanks to Mrs. Harold F. McCormick for her generous help in the production of this book.

C. G. JUNG.

June, 1917.