The World as Will and Idea, Vol. II — Arthur Schopenhauer, trans. Haldane & Kemp

In spite of all that one may say, nothing is so persistently and ever anew misunderstood as Idealism, because it is interpreted as meaning that one denies the empirical reality of the external world. Upon this rests the perpetual return to the appeal to common sense, which appears in many forms and guises ; for example, as an " irresistible conviction " in the Scotch school, or as Jacobi's faith in the reality of the external world. The external world by no means presents itself, as Jacobi declares, upon credit, and is accepted by us upon trust and faith. It presents itself as that which it is, and performs directly what it promises. It must be remembered that Jacobi, who set up such a credit or faith theory of the world, and had the fortune to impose it upon a few professors of philosophy, who for thirty years have philosophised upon the same lines lengthily and at their ease, is the same man who once denounced Lessing as a Spinozist, and afterwards denounced Schelling as an atheist, and who received from the latter the well-known and welldeserved castigation. In keeping with such zeal, when he reduced the external world to a mere matter of faith he only wished to open the door to faith in general, and to prepare belief for that which was afterwards really to be made a matter of belief; as if, in order to introduce a paper currency, one should seek to appeal to the fact that the value of the ringing coin also depends merely on the stamp which the State has set upon it. Jacobi, in his doctrine that the reality of the external world is assumedp. 170 upon faith, is just exactly " the transcendental realist who plays the empirical idealist" censured by Kant in the " Critique of Pure Reason," first edition, p. 369.

The true idealism, on the contrary, is not the empirical but the transcendental.

This leaves the empirical reality of the world untouched, but holds fast to the fact that every object, thus the empirically real in general, is conditioned in a twofold manner by the subject ; in the first place materially or as object generally, because an objective existence is only conceivable as opposed to a subject, and as its idea; in the second place formally, because the mode of existence of an object, i.e., its being perceived (space, time, causality), proceeds from the subject, is prearranged in the subject.

Therefore with the simple or Berkeleian idealism, which concerns the object in general, there stands in immediate connection the Kantian idealism, which concerns the specially given mode or manner of objective existence.

This proves that the whole material world, with its bodies, which are extended in space and, by means of time, have causal relations to each other, and everything that depends upon this — that all this is not something which is there independently of our head, but essentially presupposes the functions of our brain by meant of which and in which alone such an objective arrangement of things is possible.

For time, space, and causality, upon which all those real and objective events rest, are themselves nothing more than functions of the brain ; so that thus the unchangeable order of things which affords the criterion and clue to their empirical reality itself proceeds only from the brain, and has its credentials from this alone.

All this Kant has expounded fully and thoroughly ; only he does not speak of the brain, but calls it " the faculty of knowledge. Indeed he has attempted to prove that when that objective order in time, space, causality, matter, &c, upon which all the events of the real world ultimately rest, is properly considered, it cannot even be conceived as a self-existing order, i.e., an order of the thing in itself,

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or as something absolutely objective and unconditionally given, for if one tries to think this out it leads to contradictions. To accomplish this was the object of the antinomies, but in the appendix to my work I have proved the failure of the attempt. On the other hand, the Kantian doctrine, even without the antinomies, leads to the insight that things and the whole mode of their existence are inseparably bound up with our consciousness of them. Therefore whoever has distinctly grasped this soon attains to the conviction that the assumption that things also exist as such, apart from and independently of our consciousness, is really absurd. That we are so deeply involved in time, space, causality, and the whole regular process of experience which rests upon them, that we (and indeed the brutes) are so perfectly at home, and know how to find our way from the first — this would not be possible if our intellect were one thing and things another, but can only be explained from the fact that both constitute one whole, the intellect itself creates that order, and exists only for things, while they, on the other hand, exist only for it.