Human beings have interests toward which they retain a varying degree of freedom. They may be preoccupied with specific thoughts and ideas; they may be specifically interested in the one or the other group of objects or data. These interests may appear to be theoretic. A person may, for instance, have a great interest in railroads, pictures, landscapes, clothes or flowers. However, such an interest never remains in the sphere of contemplation alone. It sooner or later leads to actions. The person interested in landscapes will have to travel in order to see them or at least have to go to places where painting and pictures are exhibited, or he may have to paint and photograph them himself. The person interested in technical problems will sooner or later start to construct, or at least to collect. Interests of this type may be worth while and may mean the lifework or