But not only the perception of the external world, or the consciousness of other things, is conditioned by the brain and its functions, but also self‐consciousness. The will in itself is without consciousness, and remains so in the greater part of its phenomena. The secondary world of idea must be added, in order that it may become conscious of itself, just as light only becomes visible through the bodies which reflect it, and without them loses itself in darkness without producing any effect. Because the will, with the aim of comprehending its relations to the external world, produces a brain in the animal individual, the consciousness of its own self arises in it, by means of the subject of knowledge, which comprehends things as existing and the _ego_ as willing. The sensibility, which reaches its highest degree in the brain, but is yet dispersed through its different parts, must first of all collect all the rays of its activity, concentrate them, as it were, in a focus, which, however, does not lie without, as in the case of the concave mirror, but within, as in the convex mirror. With this point now it first describes the line of time, upon which, therefore, all that it presents to itself as idea must exhibit itself, and which is the first and most essential form of all knowledge, or the form of inner sense. This focus of the whole activity of the brain is what Kant called the synthetic unity of apperception (_cf._ vol. ii. p. 475). Only by means of this does the will become conscious of itself, because this focus of the activity of the brain, or that which knows, apprehends itself as identical with its own basis, from which it springs, that which wills; and thus the _ego_ arises. Yet this focus of the brain activity remains primarily a mere subject of knowledge, and as such capable of being the cold and impartial spectator, the mere guide and counsellor of the will, and also of comprehending the external world in a purely objective manner, without reference to the will and its weal or woe. But whenever it turns within, it recognises the will as the basis of its own phenomenon, and therefore combines with it in the consciousness of an _ego_. That focus of the activity of the brain (or the subject of knowledge) is indeed, as an indivisible point, simple, but yet is not on this account a substance (soul), but a mere condition or state. That of which it is itself a condition or state can only be known by it indirectly, as it were through reflection. But the ceasing of this state must not be regarded as the annihilation of that of which it is a state. This _knowing_ and conscious _ego_ is related to the will, which is the basis of its phenomenal appearance, as the picture in the focus of a concave mirror is related to the mirror itself, and has, like that picture, only a conditioned, nay, really a merely apparent, reality. Far from being the absolutely first (as, for example, Fichte teaches), it is