But after all the psychologist has no less a right to speak of freedom. Of course his freedom cannot mean exemption from causality. Whatever happens in the psychological system must be perfectly determined by the foregoing causes. But the psychologist has good reason to discriminate between those actions which result from the normal psychophysical factors and such actions as result from broken machinery. If the brain is poisoned by alcohol or in fever, if an infectious disease has destroyed the brain cells, action is no longer the outcome of the normal cooeperation of the organs, and even those clusters of neural activities which are accompanied by the consciousness of the own personality lose their control of the motor outcome. The man in delirium or paralysis acts without causal connection with his past; the action is, therefore, not the product of his whole personality, and the psychologist is justified in calling the man unfree. But, whenever the motor response results from the undisturbed cooeperation of the normal brain parts, then the inherited equipment and the whole experience and the whole training, the acquired habits and the acquired inhibitions will count in bringing about the reaction. This is the psychological freedom of man. The unity of an interconnected composite and the freedom of causal determination through normal cooeperation of all its parts characterize the only personality which the psychologist has to recognize. IV PSYCHOLOGY AND MEDICINE We are now ready to take the first step towards an examination of the problem of curing suffering mankind. So far we have spoken only of the meaning of psychology, of its principles and of its fundamental theories as to mind and brain. We have moved in an entirely theoretical sphere. Now we approach a field in which everything is controlled by a practical aim, the treatment of the sick. Yet our discussion of psychology should have brought us much nearer to the point where we can enter this realm of medicine. Everything depends on the right point of entrance. That an influence on the inner life of man may be beneficial for his health is a commonplace truth to-day for everybody. Every serious discussion of the question has to consider which influences are appropriate, and in which cases of illness the influence on inner life is advisable. The popular treatises usually start this chapter by speaking of the "mental and moral" factors; and this coupling of mental influences and moral influences characterizes large parts of the discussions of the Christian Scientists and the Christian half-scientists. Yet we must insist that the right entrance to psychotherapy is missed if the difference between morality and mentality is not clearly recognized from the beginning. The confusion of the two harms every statement. To avoid such a fundamental mistake, we had to take the long way around and to examine carefully what psychology really means and what it does not mean.