V.
Also the ego, as well as the relation of bodies to the ego, occasions the rise of analogous seeming-problems, the character of which may be briefly presented in the following manner.
The complexes of colors, sounds, and so forth, that are commonly called bodies, we shall designate for the sake of simplicity by A B C …; the complex that is known as our own body, and which constitutes a part of the former, we shall call K L M …; the complex composed of volitions, memory-images, and the like, we shall represent by α β γ. Usually, now, the complex α β γ … K L M … is opposed as ego, to the complex A B C … regarded as world of substance; sometimes, too, α β γ … is comprehended as ego, and K L M … A B C … comprehended as world of substance. Now A B C … first appears as independent of the ego. But this independence is only relative, and gives way before closer inspection. Much, it is true, may change in the complex α β γ … without much becoming noticeable in A B C …; and so vice versa. But many changes in α β γ … pass, by way of changes in K L M …, over to A B C …; and vice versa. (As, for example, when vivid ideas break forth into acts, or our environment brings about perceptible changes in our body.) At the same time K L M … appears to be more closely connected with α β γ … and A B C … respectively, than the latter do with one another; relations that find their commonest expression in thought and speech.
Closely examined, however, it appears that A B C … is always determined with and by K L M. A die, when seen close at hand, looks large; when seen at a distance, small; it looks different with the right eye from what it does with the left; sometimes it appears double; with closed eyes it is invisible. The properties of the same body, therefore, appear as modified by our own body; they appear as conditioned by it. But where, pray, is this same body that phenomenally appears so different? All that can be said is, that different A B C … are annexed to different K L M.[18]
[18] I expressed this thought many years ago (in the Vierteljahrsschrift für Psychiatrie, Leipsic and Neuwied, 1868: Ueber die Abhängigkeit der Netzhautstellen von einander) as follows: The expressions "sense-deception" and "illusion of the senses" prove, that we are not yet fully conscious, or at least that we have not yet found it necessary to incorporate this consciousness into our ordinary terminology, that the senses represent things neither wrongly nor correctly. All that can be truly said of the sensory organs is, that, under different circumstances they produce different sensations and perceptions. Since these "circumstances" are of so extremely manifold a character, being partly external (inherent in the objects), partly internal (inherent in the sensory organs), and partly interior (having the seat of their activity in the central organs), it would naturally seem, especially when attention is paid only to external circumstances, that an organ acts differently under like conditions. And it is customary to call the unusual effects, deceptions or illusions.
We see an object with a point S. If we touch S, that is bring it into relation with our body, we receive a prick. We can see S, without feeling the prick. But as soon as we feel the prick we find S. The visible point therefore is a permanent fact or nucleus, to which the prick is annexed, according to circumstances, as something accidental. From the frequency of occurrences analogous to this we ultimately accustom ourselves to regard all properties of bodies as "effects" proceeding from permanent persistent nuclei and conveyed to the ego through the mediation of the body; which effects we call sensations. By this very operation, however, these imagined nuclei lose their entire sensory content, and become mere mental symbols. The assertion is correct then that the world consists only of our sensations. In which case we have knowledge only of sensations, and the assumption of the nuclei mentioned, as well as of a reciprocal action between the same, from which sensations might be supposed originally to proceed, turns out to be wholly idle and superfluous. Such a view can only suit a halting realism or a half-matured philosophic criticism.