This proposition seems to be highly acceptable because it stands upon the principle of a conservation of substance and attempts to represent the phenomenon of consciousness as due to a transformation. But does it for that reason remove the difficulties of the doctrine of a double-faced unity of nature, which, as Mr. Russell says, “is open to the charge of being arbitrary and brings no access of insight”? Is not perhaps the term double-faced unity (which is none of my invention, and which I have been careful to avoid) a misleading and unsatisfactory term? Why should nature be double-faced? Why are feeling and motion the only two attributes of natural phenomena? Is this not arbitrary? Could nature not be just as well a treble or quadruple-faced unity. Nature might possess, as Spinoza actually declares, infinite attributes of which these two only, viz. extension and thought, i. e. motion and feeling, happen to be known to us. It is this apparent arbitrariness which bars our insight and deprives us of the satisfaction that ought to attend the real solution of a problem. But let us avoid the term double-faced unity; let us speak of the subjectivity and the objectivity of nature, and the clouds will disappear. The doctrine of a double-faced unity has been criticised as dualism, and the proposition that nature consists of two radically different attributes—exactly of two, not more and not less—must most decidedly appear as dualism. But is it dualistic to say that every subject appears to its objects not as a subject but as an object among other objects? Certainly not. The relativity of the terms subject and object affords us the key to a comprehension of the situation. This world of ours is a world of relations. The phenomena of nature exhibit an unceasing activity; they consist of constant changes, and every change, every motion, has a whence and a whither. Every transformation is a series of events among which any prior one is called cause and any subsequent one effect. If we regard feeling and motion as two attributes of nature, we are actually on the brink of dualism, and we shall understand how Spinoza, in order to escape from dualism and arrive at a monistic view, assumed without any plausible argument the existence of an infinite number of attributes. This assumption however is of no avail, for the problem would arise: How is it that we know only two of all these infinite attributes? Why do we not know any other? and why are we unable to form even a dim notion of any other? If they exist why do they exhibit no effects upon us? Perhaps because we ourselves and this world of ours consist only of two! And if they exhibit no effects upon us and upon our world, can they be said to exist at all? Might we not, in that case, consider them as non-existent and count the two known attributes alone as actual realities? Thus the dualism would remain; and Spinoza’s monism is only apparent.