conception, is closely related to the philosophy of romanticism. But Wundt's idealism has been attained by the method of scientific investigation even to a greater extent than in the case of Lotze, Hartmann and Fechner.
The psychological motives to philosophizing sprang from Wundt's investigations of the physiology of the senses. He recognized the fact that the theory of space could only arise from primary sensations by means of a creative synthesis, a synthesis whose product possesses other attributes than the elements, considered by themselves. Afterwards, while investigating the temporal progress of ideas, he came upon the problem of psychical integration (which he later called Apperception). This completed the foundation for the fundamental theories of his psychology. His Grundzüge der physiologischen Psychologie (1874, 6th ed., 1908) treats the psychological problems which can be elucidated physiologically and experimently with great thoroughness, and describes the methods and instruments of experimentation. Wundt assumes the parallelism of the physical and the psychical as a preliminary hypothesis; the difference is only a difference of viewpoint. But in its ultimate analysis he regards the psychical viewpoint as fundamental. And in his view the only necessity for assuming physiological correlates is due to the individual psychical elements which constitute the content of psychical life, not for the forms or the combinations of the elements, nor for experiences of value.
Wundt construes psychical life as pure activity. The assumption of a psychical "substance" involves the application of materialistic ideas to the sphere of spiritual reality. Psychical activity is especially evident in the form of apperception in its function of attention, associa-
