But the final aim was the causal connection. The appearance and disappearance of those millions of elements and their connection had to be explained. We recognized that such an explanation of the contents of consciousness was possible only through the connections between the accompanying brain processes. Every psychical change had to be conceived as parallel to a physiological change. The psychology which is to be the basis of psychotherapy had to be therefore a physiological psychology.

We recognized that these psychophysiological processes were processes of transmission between impressions and expressions, that is, between incoming nervous currents and outgoing nervous currents, between stimuli and reactions. Thus we have no central process which is not influenced by the surroundings and which is not at the same time the starting point of an action. We have normal health of the personality as long as there is a complete equilibrium in the functions of the organism which adjusts the activities to the surroundings. Every abnormality is a disturbance of this equilibrium. A psychology which is the basis of psychotherapy thus conceives every mental process in relation to both the ideas and the actions; it avoids all one-sidedness by which the mind is cut off either from its resources or from its effects. The relations to the impressions are usually the less neglected: and we must the more emphasize the fact that the psychology needed for psychotherapy knows no mental fact which does not start an action and that every change in the system of actions involves a change in the central experience. Wherever this equilibrium of adjusted functions is disturbed, some therapy of the physician has to set in: whether psychotherapy is in order depends upon the special conditions.

We have recognized that there are no mental facts outside of those which are in consciousness and that from a psychological point of view consciousness itself does not have different degrees and different levels, that all varieties of experience refer thus only to the special content and its organization. There is thus no subconscious. On the other hand, we saw that there is no conscious experience which is not based on a bodily brain process. By these two fundamental facts of scientific psychology, every possible psychotherapy gets from the start its clear middle way between two extreme views which are popular today. The one school nowadays lives from the contrast between consciousness and subconsciousness and makes all psychotherapy work with and through and in the subconscious. The other school creates a complete antithesis between mind and body and makes psychotherapy a kind of triumph of the mind over the body. Practically every popular treatise on psychotherapeutic subjects in recent years belongs to the one or the other group; and yet both are fundamentally wrong. And while, of course, this mistake is one of theoretical interpretation, it evidently has its practical consequences. The fantastic position allowed to a subconscious mind easily gives to the doctrine a religious or even a mystical turn and the artificial separation between the energies of the mind and those of the body leads easily to a moral sermon. Whether this amalgamation of medicine with religion or with morality may not be finally dangerous to true morality and true religion is a question which will interest us much later. Here we only have to ask whether it is not harmful to the interests of the patient and thus to the rights of medicine, and indeed that must be evident here at the very threshold. Both schools must have the tendency to extend psychotherapy at the expense of bodily therapy and to narrow down psychotherapy itself to a therapy by appeals which in the one case are suggestions to the subconscious and in the other case persuasions and encouragements to the conscious will. As soon as we have overcome the prejudices of those two rival schools and have recognized that both are wrong, that there is no subconscious and that there is no psychological fact which is not at the same time a physiological one, we see at once that this common procedure of both schools is unjustified and dangerous. Mental therapy and physical therapy ought to be most intimately connected parts of the same therapeutic effort and mental therapy includes by far more than mere suggestions and appeals. All that involves of course that its systematic application belongs in the hands of the well-trained physician and of nobody else, but on the other hand, it involves that every physician ought to be well schooled in psychology.

As soon as a disturbance to be cured is considered as a lack of equilibrium in psychophysical functions, every mental influence, every suggestion and appeal becomes itself an excitement or an inhibition of nerve cells. The sharp demarcation line between a psychical agency and a physical one disappears altogether; the spoken word is then considered as physical airwaves which stimulate certain brain centers and in the given paths this stimulation is carried to hundreds of thousands of neurons. The protracted warm bath or the cold douche influences, too, large brain parts by changing the blood circulation which controls the activity of those neurons; or the bromides absorbed in the digestive apparatus, or the morphine injected, also reach the neurons and again have a different kind of influence on them, and the electric current may stimulate the nervous system in still a different way. It may be, and under many conditions certainly is, essential to influence the brain cells just in that particular way which results from the spoken word, but there too the causal influence remains a function of the physical effect and thus by principle there is no sharp separation from other physical means. Thus to believe in psychotherapy ought never to mean that we have a right to make light of the other means which, as experience shows, may help towards the treatment of disturbances in the central equilibrium. Suggestions and bromides together may secure an effect which neither of them alone will bring about. It is most unfortunate that not without some guilt on the part of the physicians themselves, the large public has begun to believe that orthodox psychotherapy has to mean a rejection of drugs and a contempt for the doctors who prescribe them.

Of course a discussion of psychotherapy cannot enter into the study of these physical agencies of treatment, but at the threshold, we have to insist that there exists no opposition between psychophysiological and physiological means of influencing the brain. It may be true that drugs and baths and electricity have no influence on the subconscious, but the trouble is not that the drugs are inefficient but that they cannot influence what does not exist. In the same way disappears now that new boundary line for psychotherapy which wants to limit it to mere suggestion and appeal. If psychotherapy employs all the means by which we can influence mental states in the interest of the health of the personality, we have no reason to confine it either to a persuasion of the subconscious through suggestion and hypnotism or a persuasion of the conscious, in which it works as a moral appeal. Suggestion and hypnotism certainly must play a large part in psychotherapy and that part does not become smaller by the fact that we reject the subconscious interpretation of them and consider them entirely as psychophysical processes. And in the same way undoubtedly we have to acknowledge the psychophysiological effect of persuasion and of the appeals to the conscious intellect and will. But for us as psychotherapists all those factors have no moral value but only a therapeutic one, and thus stand in line with any other influence that may help, even though from a purposive point of view it stands on a much lower level. A mere mental distraction by enjoyment and play and sport, an æsthetic influence through art, a mere stimulus to automatic imitation, an enforced mental rest, an involuntary discharge of suppressed ideas, and many similar schemes and even tricks of the mental physician belong with the same right to psychotherapy.

It is really doubtful whether the moral and religious appeals are always helpful and not sometimes or often even dangerous for the health of the individual; and it is not doubtful that morally and religiously indifferent mental influences are often of the highest curative value. The more we abstract from everything which suggests either the mysticism of the subconscious or the moral issues of a mind which is independent of the body, the more we shall be able to answer the question as to the means by which health can be restored. This question is neither a moral nor a philosophical one but strictly one of experience. In this connection, we must remember that we also have had to give up the artificial demarcation line between organic and functional diseases. We recognized that every so-called functional disease has its organic basis too, and that it is entirely secondary whether we are able to find visible traces of the organic disturbance. We had to acknowledge, to be sure, the difference between reparable and irreparable disturbances, but such grouping expresses only in another form the fact that experience alone can show whether the methods of treatment which we know so far will be successful or not. Not a few disturbances of the equilibrium which appeared irreparable to an earlier time yield to the treatment of to-day, and no one can determine whether much which appears irreparable today may not be accessible either to psychotherapeutic or to physical therapeutic means to-morrow. If we were carelessly to identify the reparable troubles with those which we cannot recognize visibly, we should be at a loss to understand why, for instance, many forms of insanity are entirely beyond our psychotherapeutic influences. On the other hand, every physician who uses psychotherapeutic means is surprised to see the effective bodily readjustment where serious disturbances perhaps of the circulatory system or the digestive system existed. What the methods can do and what they cannot do must simply be left to experience, but of course to an experience which is eager to expand itself by ever new experimental curative efforts.

From this point of view we can see clearly the general division of the whole field of possible psychotherapy. Psychotherapy influences psychophysical states in the interest of health. There are only two possibilities open: either the disturbance is in the psychophysical system itself or it is outside of it, that is in the other parts of the body which are somehow under the influence of the mind. In the first case when the disturbance occurs in the mind-brain system itself, we ought to separate two large groups, first those cases in which the system itself is normal and the disturbance comes from without, and second those in which the constitution of the system itself was abnormal and led to disturbances under conditions in which a normal system would not have suffered. We have to consider both groups somewhat more in detail, as each again allows a large variety of cases.

Thus we have before us, first the normal mind-brain system into which a disturbance breaks, injuring more or less severely and for a longer or shorter time the equilibrium of the psychophysical functions. Here belong any bodily processes which produce pain or any bodily defects which produce blanks in the content of consciousness; the pain of sciatica or of rheumatism, or the defect of the blind or of the deaf, certainly interferes in a disturbing way with the perfect harmony of psychophysical activities. But here also belongs the suffering which results from conditions in the surroundings, the loss of a friend, a disappointment in life, any source of worry and grief. Social and bodily conditions alike may thus work to break up the equilibrium. The pain sensation interferes with the normal flow of mental life and the grief may undermine the mental interests. The psychotherapeutic effort may be directed toward removing the source of the disturbance, bringing the patient under other conditions, curing the diseased organ, and where that is not possible, may work directly on the psychophysical state, inhibiting the pain, suppressing the emotion, substituting pleasant ideas, distracting the whole mind, filling it with agreeable feelings, until the normal equilibrium is restored.

The psychophysical system itself was not really harmed by such influences. In the following groups, such is no longer the case. We here think at first of those severe injuries which have their sources in abnormal processes outside of the brain. The anæmia of the patient or the low state of his nutrition or the fever heat of his blood impairs the harmony of the mental functions. Another and for the psychotherapist much more important group is that in which the impairment results from toxic influences. Alcohol, morphine, cocaine, tobacco, and many other drugs may have been misused and may have produced a most marked alteration in the mind-brain system. Desires may have developed which completely destroy the balance of the normal functions and yet the satisfaction of which increases the poisoning effect. But here belongs further the effect of poisons which the body itself produces: the toxic disturbance of uræmia or the coma in diabetes, or especially the grave disturbances resulting from the abnormal action of the thyroid gland, the source of cretinism. Many indications suggest that a near future will consider this group much larger than we are really justified in doing today, probably soon connecting a number of other mental diseases like dementia præcox with toxic effects of bodily origin. Experience shows that in this group not a few chances exist for successful psychotherapeutic influence. Yet the means may be various in character and their effect may be a direct or an indirect one. A psychical shock may remove directly the mental disturbance of the alcoholic state, but it is more important that mental suggestion can remove the alcoholic disturbance indirectly by suppressing the desire for alcoholic excesses. Even where cure by psychotherapeutic means is out of the question, as is the case with feverish delirium or uræmic excitements, no skilled physician ignores the aid which a well-adjusted mental influence can offer to the patient.

We come to a third group. Some outside cause has harmed the central nervous system directly, and has left it in a disabled state after the cause itself has disappeared. Such causes may have been at first purely functional: for instance, a neglect of training, or a wrong training, or an over-activity, but the ill-adjusted function which involved, of course, every time an ill-adjusted organic activity or lack of activity, has led to a lasting or at least relatively lasting disturbance in the system of paths. The neglect of training, for instance, in periods of development may have resulted in the retardation which yields the symptoms of a feeble-minded brain, or the wrong training may have created vicious habits, firmly established in the mind-brain system and gravely disturbing the equilibrium. Above all, the overstrain of function, especially of emotional functions, may lead to that exhaustion which produces the state of neurasthenia. It is true that not a few would doubt whether we have the right to class neurasthenia here where we speak of the harm done to the normal brain. Many neurologists are inclined to hold that neurasthenia demands a special predisposition and is therefore dependent upon a neurotic constitution of the brain itself. But if defenders of such a view, as for instance, Dubois, acknowledge that "we might say that everybody is more or less neurasthenic," we can no longer speak of any special predisposition. Certainly there exists a constitutional neurasthenia sometimes but we have hardly a right to deny that overstrain in the brain activity may produce a series of neurasthenic symptoms in any brain, and the special predisposition is responsible rather for the particular selection among the innumerable symptoms.