what is involved in the implied distinction between mind and body,[1] but even granting the possibility of the most various interpretations of these terms, it remains true that the child does not conceive the objects apprehended as being representative images or copies of external bodies. The statements of Herbart and Avenarius are therefore in flagrant contradiction with the facts. .Realism is the fundamental characteristic of the standpoint of primitive man and of the child-mind, and the considerations which lead to subjective idealism, even in the Cartesian form, are quite beyond their range of vision.
The true originating cause of subjective idealism seems to me to be physiological. Subjective idealism was not definitely formulated until the physiology of the nervous system had been developed by Descartes and his contemporaries;[2] and the fundamental reason which inclined them to subjective idealism may perhaps be stated in the following simple manner. So long as the eyes can be regarded as windows through which the mind can look out, every observer may directly apprehend the real external objects. But when it is discovered that the eyes are not exits but always only entrances, that they are not passages through which the mind may issue out but only channels through which currents pass into the brain, the mind then appears to be shut off from direct communion with the external objects, and to depend for all its knowledge on mental images which in a mysterious manner accompany the brain-states. These physiological considerations apply as directly to my own experience as to that of others, and so, on the same identical grounds, I may infer that both my own experience and that of other men, though an apparently immediate apprehension of an external world, is purely subjective. Avenarius explicitly disavows this explanation.[3] Nowhere, however, does he consider it, much less refute it.
I should further contend that the subjectivist position is not a falsification of the attitude of naive realism but a necessary step on the way to its correction. Subjective idealism may not itself be true, but the facts upon which it is based suffice to prove that naïve realism is certainly false. In the
- ↑ Cf. below, p. 156.
- ↑ So far as subjective idealism appears in Greek philosophy, as for instance in the philosophy of Democritus, it involves, and would seem to be due to, physical and physiological considerations.
- ↑ Vierteljahrsschrift, vol. xviii., “Bemerkungen,” p. 419, § 116: “Diese logisch unberechtigte Deutung der Abhängigkeit der ‘Farben,’ ‘Gefühle’ u. s. w. vom Gehirn ist nicht der Grund der Introjection, sondern ihre Folge.”
