Hence, we must not speak of “red,” “sweet,” “hot,” etc., as being symbols, or signs, which as such are only aroused within us, and to which “outside” of us something totally different corresponds. For that which is really set going within us, as the effect of some external happening, is something altogether other than what appears in the field of our sensations. If we want to call that which is within us a symbol, then we can say: These symbols make their appearance within our organism, in order to mediate to us the perceptions which, as such, in their immediacy, are neither within nor outside of us, but belong, on the contrary, to that common world, of which my “external” world and my “internal” world are only parts. In order to be able to grasp this common world, I must, it is true, raise myself to that higher plane of knowledge, for which an “inner” and an “outer” no longer exist. (I know quite well that people who pride themselves on the gospel that our entire world of experience builds itself up out of sensations and feelings of unknown origin will look contemptuously upon these remarks; as, for instance, Dr. Erich Adikes in his book, _Kant contra Haeckel_, observes condescendingly: “At first people like Haeckel and thousands of his type philosophise gaily away without troubling themselves about theory of knowledge or critical self-reflection.” Such gentlemen have no inkling of how cheap their own theories of knowledge are. They suspect the lack of critical self-reflection only in others. Let us leave to them their “wisdom.”) Nicholas of Cusa expresses some very telling thoughts bearing directly upon this very point. The clear and distinct way in which he holds apart the lower and the higher knowledge enables him, on the one side, to arrive at a full and complete recognition of the fact that man as a sense-being can only have in himself processes which, as effects, must necessarily be altogether unlike the corresponding external processes; while, on the other side, it guards him against confusing the inner processes with the facts which make their appearance in the field of our perceptions, and which, in their immediacy, are neither outside nor inside, but altogether transcend this opposition of “in” and “out.”