Ist nicht der Kern der Natur
Menschen im Herzen?”
—Goethe.
Chapter XVIII.[29] On The Possibility Of Knowing The Thing In Itself.
In 1836 I already published, under the title “Ueber den Willen in der Natur” (second ed., 1854; third ed., 1867), the most essential supplement to this book, which contains the most peculiar and important step in my philosophy, the transition from the phenomenon to the thing in itself, which Kant gave up as impossible. It would be a great mistake to regard the foreign conclusions with which I have there connected my expositions as the real material and subject of that work, which, though small as regards its extent, is of weighty import. These conclusions are rather the mere occasion starting from which I have there expounded that fundamental truth of my philosophy with so much greater clearness than anywhere else, and brought it down to the empirical knowledge of nature. And indeed this is done most exhaustively and stringently under the heading “Physische Astronomie;” so that I dare not hope ever to find a more correct or accurate expression of that core of my philosophy than is given there. Whoever desires to know my philosophy thoroughly and to test it seriously must therefore give attention before everything to that section. Thus, in general, all that is said in that little work would form the chief content of these supplements, if it had not to be excluded on account of having preceded [pg 400] them; but, on the other hand, I here take for granted that it is known, for otherwise the very best would be wanting.
I wish now first of all to make a few preliminary observations from a general point of view as to the sense in which we can speak of a knowledge of the thing in itself and of its necessary limitation.
What is knowledge? It is primarily and essentially idea. What is idea? A very complicated physiological process in the brain of an animal, the result of which is the consciousness of a picture there. Clearly the relation between such a picture and something entirely different from the animal in whose brain it exists can only be a very indirect one. This is perhaps the simplest and most comprehensible way of disclosing the deep gulf between the ideal and the real. This belongs to the things of which, like the motion of the earth, we are not directly conscious; therefore the ancients did not observe it, just as they did not observe the motion of the earth. Once pointed out, on the other hand, first by Descartes, it has ever since given philosophers no rest. But after Kant had at last proved in the most thorough manner the complete diversity of the ideal and the real, it was an attempt, as bold as it was absurd, yet perfectly correctly calculated with reference to the philosophical public in Germany, and consequently crowned with brilliant results, to try to assert the absolute identity of the two by dogmatic utterances, on the strength of a pretended intellectual intuition. In truth, on the contrary, a subjective and an objective existence, a being for self and a being for others, a consciousness of one's own self, and a consciousness of other things, is given us directly, and the two are given in such a fundamentally different manner that no other difference can compare with this. About himself every one knows directly, about all others only very indirectly. This is the fact and the problem.
Whether, on the other hand, through further processes [pg 401] in the interior of a brain, general conceptions (Universalia) are abstracted from the perceptible ideas or images that have arisen within it, for the assistance of further combinations, whereby knowledge becomes rational, and is now called thinking—this is here no longer the essential question, but is of subordinate significance. For all such conceptions receive their content only from the perceptible idea, which is therefore primary knowledge, and has consequently alone to be taken account of in an investigation of the relation between the ideal and the real. It therefore shows entire ignorance of the problem, or at least it is very inept, to wish to define that relation as that between being and thinking. Thinking has primarily only a relation to perceiving, but perception has a relation to the real being of what is perceived, and this last is the great problem with which we are here concerned. Empirical being, on the other hand, as it lies before us, is nothing else than simply being given in perception; but the relation of the latter to thinking is no riddle, for the conceptions, thus the immediate materials of thought, are obviously abstracted from perception, which no reasonable man can doubt. It may be said in passing that one can see how important the choice of expressions in philosophy is from the fact that that inept expression condemned above, and the misunderstanding which arose from it, became the foundation of the whole Hegelian pseudo-philosophy, which has occupied the German public for twenty-five years.