We know now that inner life can be looked on from two entirely different standpoints: a purposive one and a causal one, and we have seen that these two ways of looking on inner life bring about entirely different aspects of man's inner experience, serve different aims, and stand in different relations to the immediate needs of our real life. We know that the one, the causal aspect, belongs to psychology, while the non-psychological, the purposive aspect, belongs to our immediate mutual understanding in the walks of life. If the physician is to make use of inner experience in the interests of overcoming sickness, he must first decide whether to take the causal or the purposive point of view in dealing with the patient's mind. This problem is too carelessly ignored and through that neglect arises much of the popular confusion. Of course just this carelessness becomes in some ways the ground for apparent strength for many a superstition and prejudice. If the doors of the causal mind and of the purposive mind are both open, and the spectator does not notice that there are two, any trick on thought and reason can easily be played. Whatever cannot pass through the causal door slips in through the other, and whatever does not go in through the door of purpose marches through the entrance of causality. With such methods anything can be proved, and the most unscrupulous doctrines can be nicely demonstrated. If we are to avoid such logical smuggling, we must see clearly which attitude towards mental life belongs properly to the domain of psychotherapy. But what we have discussed now leaves little doubt as to the necessary decision. The physician is interested in the mental life with the aim of producing a certain effect, namely, that of health. Thus the mental life of the whole personality comes in question for him as belonging to a chain of causes and effects; whichever levers he may move, everything is to be a cause which, in accordance with causal laws, is to produce a certain change. Inner life is thus, in the interests of medical treatment, necessarily a part of a causal system. This means the standpoint of scientific psychology is the only adequate one. The purposive view of inner life ought not to be in question when the patient enters the doctor's office.