The view, for example, that all the contents of psychical experience are ideas, and that these ideas are more or less permanent objects, would hardly be comprehensible without such presuppositions. That this concept is really foreign to psychology, is further attested by the close interconnection in which it stands to the concept of material substance. It is regarded either as identical with the latter or else as distinct in nature, but still reducible in its most general formal characteristics to one of the particular forms of the concept matter, namely to the atom .
5. Two forms of the concept mind-substance may be distinguished, corresponding to the two types of metaphysical psychology pointed out above (§ 2, p. 6). The one is materialistic and regards psychical processes as the activities of matter or of certain material complexes, such as the brain-elements. The other is spiritualistic and looks upon these processes as states and changes in an extended and therefore invisible and permanent being of a specially spiritual nature. In this case matter is thought of as made up of similar atoms of a lower order (monistic, or monado-logicial spiritualism), or the mind-atom is regarded as specifically different from matter proper (dualistic spiritualism) (comp. p. 7).
In both its materialistic and spiritualistic forms, the concept mind-substance does nothing for the interpretation of psychological experience. Materialism, does away with psychology entirely and puts in its place an imaginary brain-[p. 314] physiology of the future, or when it tries to give positive theories, falls into doubtful and unreliable hypotheses of cerebral physiology. In thus giving up psychology in any proper sense, this doctrine gives up entirely the attempt to furnish any practical basis for the mental sciences. Spiritualism allows psychology is such to continue, but subordinates actual experience to entirely arbitrary metaphysical hypotheses, through which the unprejudiced observation of psychical processes is obstructed.
This appears first of all in the incorrect statement of the problem of psychology, with which the metaphysical theories start. They regard inner and outer experience is totally heterogeneous, though in some external way interacting, spheres.
6. It has been shown (§ 1, p. 3) that the experience dealt with in the natural sciences and in psychology are nothing but components of one experience regarded from different points of view: in the natural sciences as an interconnection of objective phenomena and, in consequence of the abstraction from the knowing subject, as mediate experience; in psychology as immediate and underived experience.
When this relation is once understood, the concept of a m ind-substance immediately gives place to the concept of the actuality of mind as a basis for the comprehension of psychical processes. Since the psychological treatment of experience is supplementary to that of the natural sciences, in that it deals with the immediate reality of experience, it follows naturally that there is no place in psychology for hypothetical supplementary concepts such as are necessary in the natural sciences because of their concept of an object independent of the subject. In this sense, the concept of the actuality of mind does not require any hypothetical determinants to define its particular contents, as the concept [p. 315] of matter does, but quite to the contrary, it excludes such hypothetical elements from the first by defining the nature of mind as the immediate reality of the processes themselves. Still, since one important component of these processes, namely the totality of ideational objects, is at the same time the subject of consideration in the natural sciences, it necessarily follows that substance and actuality are concepts that refer to one and the same general experience with the difference that in each case this experience is looked at from a different point of view. If we abstract from the knowing subject in our treatment of the world of experience, it appears, is a manifold of interacting substances; if, on the contrary, we regard it as the total content of the experience of the subject including the subject itself, it appears as a manifold of interrelated occurrences.
In the first case, phenomena are looked upon as outer phenomena, in the sense that they would take place just the same, even if the knowing subject were not there at all, so that we may call the form of experience dealt with in the natural sciences outer experience. In the second case, on the contrary, all the contents of experience are regarded as belonging directly to the knowing subject, so that we may call the psychological attitude towards experience that of inner experience. In this sense outer and inner experience are identical with mediate and immediate, or with objective and subjective forms of experience. They all serve to designate, not different spheres of experience, but different supplementary points of view in the consideration of an experience which is presented to us as an absolute unity.