Abstraction is an activity pertaining to the psychological functions in general. There is an abstract thinking, just as there is abstract feeling, sensation, and intuition. The whole psychology of an individual even in its most fundamental features is oriented in accordance with his habitual attitude. The idea is a psychological factor that not only determines thinking but, as a practical idea, also conditions feeling. The degree of psychological efficacy of the primordial image is determined by the attitude of the individual. If the attitude is introverted, the natural consequence of the withdrawal of libido from the external object is the heightened significance of the internal object. The psychological individual is characterized by a peculiar and in some respects unique psychology. The peculiar nature of the individual psyche appears less in its elements than in its complex formations. Sensation is strongly developed in children and primitives, since in both cases it predominates over thinking and feeling, though not necessarily over intuition.