the vibrations which condition colour may be distinguished from colour as reality from appearance, in the same sense in which it may be said that the difference of the white colour of my paper before the perception of a red card from the green colour of the paper after the perception resolves itself into the distinction between a really white and an apparently green object? Such a statement must involve one or other of the three following positions:[1] (1) If the cinnabar communicates a certain rate of vibration to the ether, and the sense-organ stimulated by these vibrations is completely normal, then the cinnabar is red; but if the organ is abnormal it appears different, for instance, to the red-blind black. (2) If the cinnabar communicates a certain rate of vibration to the ether, it depends on the special nature of the sense-organ whether the cinnabar appears red or black. (3) If the cinnabar by means of ether vibrations stimulates our nervous system and thereby causes the sensation of red or black, then these colours, and colours in general, are quite incomparable with their cause, and accordingly are not properties descriptive of the cinnabar as an actually existing thing, but only of its appearance.
No one of these three positions is tenable. As regards the first position, the statement that the cinnabar appears but is not black to the red-blind observer is contrary to fact. The statement can only be made by a normal individual who in setting himself at the point of view of the abnormal observer still retains his own. In describing the abnormal as unreal, he illegitimately assumes that difference of standpoint (and that in this case means for Avenarius different constitution of the nervous system) should involve no difference in the content apprehended; in other words, that the object exists out of relation to the self, and that it has a particular nature and colour in and by itself. The second position involves the same fallacy in an aggravated form. The illegitimate interpretation first made by the normal observer of the object of the abnormal observer is, by a further confusion, extended to the object of his own observation. It therefore misrepresents normal perception as completely as the first position misrepresents the abnormal. The third position, while equally untenable, brings the determining assumptions—and they are of course those involved in the process of introjection—more clearly into view. We may, in the first place, note that even if colour is an effect of which ether-vibrations are the cause, that does not justify us in describing it as appear-
- ↑ Loc. cit., § vii.
