We become most vividly conscious of the glaring contrast between the two methods of considering the intellect opposed to each other above if we carry the matter to the extreme and realise that what the one, as reflective thought and vivid perception, directly assumes and makes its material is for the other nothing more than the physiological function of an internal organ, the brain; nay, that we are justified in asserting that the whole objective world, so boundless in space, so infinite in time, so unsearchable in its perfection, is really only a certain movement or affection of the pulpy matter in the skull. We then ask in astonishment: what is this brain whose function produces such a phenomenon of all phenomena? What is the matter which can be refined and potentiated to such a pulp that the stimulation of a few of its particles becomes the conditional supporter of the existence of an objective world? The fear of such questions led to the hypothesis of the simple substance of an immaterial soul, which merely dwelt in the brain. We say boldly: this pulp also, like every vegetable or animal part, is an organic structure, like all its poorer relations in the inferior accommodation of the heads of our irrational brethren, down to the lowest, which scarcely apprehends at all; yet that organic pulp is the last product of nature, which presupposes all the rest. But in itself, and outside the idea, the brain also, like everything else, is _will_. _For existing for another is being perceived; being in itself is willing_: upon this it depends that on the purely objective path we never attain to the inner nature of things; but if we attempt to find their inner nature from without and empirically, this inner always becomes an outer again in our hands,—the pith of the tree, as well as its bark; the heart of the animal, as well as its hide; the white and the yolk of an egg, as well as its shell. On the other hand, upon the subjective path the inner is accessible to us at every moment; for we find it as the _will_ primarily in ourselves, and must, by the clue of the analogy with our own nature, be able to solve that of others, in that we attain to the insight that a being in itself independent of being known, _i.e._, of exhibiting itself in an intellect, is only conceivable as willing.