to that of his predecessors. First, as we have just seen, to the philosophy of Locke, confirming and extending it; secondly, to that of Hume, correcting and making use of it, a relation which is most distinctly expressed in the “Prolegomena” (that most beautiful and comprehensible of all Kant's important writings, which is far too little read, for it facilitates immensely the study of his philosophy); thirdly, a decidedly polemical and destructive relation to the Leibnitz-Wolfian philosophy. All three systems ought to be known before one proceeds to the study of the Kantian philosophy. If now, according to the above, the distinction of the phenomenon from the thing in itself, thus the doctrine of the complete diversity of the ideal and the real, is the fundamental characteristic of the Kantian philosophy, then the assertion of the absolute identity of these two which appeared soon afterwards is a sad proof of the saying of Goethe quoted above; all the more so as it rested upon nothing but the empty boast of intellectual intuition, and accordingly was only a return to the crudeness of the vulgar opinion, masked under bombast and nonsense, and the imposing impression of an air of importance. It became the fitting starting-point for the still grosser nonsense of the clumsy and stupid Hegel. Now as Kant's separation of the phenomenon from the thing in itself, arrived at in the manner explained above, far surpassed all that preceded it in the depth and thoughtfulness of its conception, it was also exceedingly important in its results. For in it he propounded, quite originally, in a perfectly new way, found from a new side and on a new path, the same truth which Plato never wearies of repeating, and in his language generally expresses thus: This world which appears to the senses has no true being, but only a ceaseless becoming; it is, and it is not, and its comprehension is not so much knowledge as illusion. This is also what he expresses mythically at the beginning of the seventh book of the Republic, the most important passage in all his writings, which has already been referred to in the third book of the present work. He says: Men, firmly chained in a dark cave, see neither the true original light nor real things, but only the meagre light of the fire in the cave and the shadows of real things which pass by the fire behind their backs; yet they think the shadows are the reality, and the determining of the succession of these shadows is true wisdom. The same truth, again quite differently presented, is also a leading doctrine of the Vedas and Puranas, the doctrine of Mâyâ, by which really nothing else is understood than what Kant calls the phenomenon in opposition to the thing in itself; for the work of Mâyâ is said to be just this visible world in which we are, a summoned enchantment, an inconstant appearance without true being, like an optical illusion or a dream, a veil which surrounds human consciousness, something of which it is equally false and true to say that it is and that it is not. But Kant not only expressed the same doctrine in a completely new and original way, but raised it to the position of proved and indisputable truth by means of the calmest and most temperate exposition; while both Plato and the Indian philosophers had founded their assertions merely upon a general perception of the world, had advanced them as the direct utterance of their consciousness, and presented them rather mythically and poetically than philosophically and distinctly. In this respect they stand to Kant in the same relation as the Pythagoreans Hicetas, Philolaus, and Aristarchus, who already asserted the movement of the earth round the fixed sun, stand to Copernicus. Such distinct knowledge and calm, thoughtful exposition of this dream-like nature of the whole world is really the basis of the whole Kantian philosophy; it is its soul and its greatest merit. He accomplished this by taking to pieces the whole machinery of our intellect by means of which the phantasmagoria of the objective world is brought about, and presenting it in detail with marvellous insight and ability. All earlier Western philosophy, appearing in comparison with the Kantian unspeakably clumsy, had failed to recognise that truth, and had therefore always spoken just as if in a dream. Kant first awakened it suddenly out of this dream; therefore the last sleepers (Mendelssohn) called him the “all-destroyer.” He showed that the laws which reign with inviolable necessity in existence, i. e., in experience generally, are not to be applied to deduce and explain existence itself that thus the validity of these laws is only relative, i. e., only arises after existence; the world of experience in general is already established and present; that consequently these laws cannot be our guide when we come to the explanation of the existence of the world and of ourselves. All earlier Western philosophers had imagined that these laws, according to which the phenomena are combined, and all of which – time and space, as well as causality and inference – I comprehend under the expression “the principle of sufficient reason,” were absolute laws conditioned by nothing, æternæ veritates; that the world itself existed only in consequence of and in conformity with them; and therefore that under their guidance the whole riddle of the world must be capable of solution. The assumptions made for this purpose, which Kant criticises under the name of the Ideas of the reason, only served to raise the mere phenomenon, the work of Mâyâ, the shadow world of Plato, to the one highest reality, to put it in the place of the inmost and true being of things, and thereby to make the real knowledge of this impossible; that is, in a word, to send the dreamers still more soundly to sleep. Kant exhibited these laws, and therefore the whole world, as conditioned by the form of knowledge belonging to the subject; from which it followed, that however far one carried investigation and reasoning under the guidance of these laws, yet in the principal matter, i. e., in knowledge of the nature of the world in itself and outside the idea, no step in advance was made, but one only moved like a squirrel in its wheel. Thus, all the dogmatists may be compared to persons who supposed that if they only went straight on long enough they would come to the end of the world; but Kant then circumnavigated the world and showed that, because it is round, one cannot get out of it by horizontal movement, but that yet by perpendicular movement this is perhaps not impossible. We may also say that Kant's doctrine affords the insight that we must seek the end and beginning of the world, not without, but within us.
All this, however, rests on the fundamental distinction between dogmatic and critical or transcendental philosophy. Whoever wishes to make this quite clear to himself, and realise it by means of an example, may do so very briefly by reading, as a specimen of dogmatic philosophy, an essay of Leibnitz entitled “De Rerum Originatione Radicali,” and printed for the first time in the edition of the philosophical works of Leibnitz by Erdmann (vol. i. p. 147). Here the origin and excellence of the world is demonstrated a priori, so thoroughly in the manner of realistic-dogmatism, on the ground of the veritates æternæ and with the assistance of the ontological and cosmological proofs. It is indeed once admitted, by the way, that experience shows the exact opposite of the excellence of the world here demonstrated; but experience is therefore given to understand that it knows nothing of the matter, and ought to hold its tongue when philosophy has spoken a priori. Now, with Kant, the critical philosophy appeared as the opponent of this whole method. It takes for its problem just these veritates æternæ, which serve as the foundation of every such dogmatic structure, investigates their origin, and finds it in the human mind, where they spring from the peculiar forms which belong to it, and which it carries in itself for the purpose of comprehending an objective world. Thus, here, in the brain, is the quarry which supplies the material for that proud dogmatic edifice. But because the critical philosophy, in order to attain to this result, was obliged to go beyond the veritates æternæ upon which all the preceding dogmatism was founded, and make these truths themselves the objects of investigation, it became transcendental philosophy. From this, then, it also follows that the objective world, as we know it, does not belong to the true being of the thing in itself, but is merely its phenomenal appearance conditioned by those very forms which lie a priori in the intellect (i. e., the brain), therefore it cannot contain anything but phenomena.
Kant, indeed, did not attain to the knowledge that the phenomenon is the world as idea, and the thing in itself is the will. But he showed that the phenomenal world is conditioned just as much through the subject as through the object, and because he isolated the most universal forms of its phenomenal appearance, i. e., of the idea, he proved that we may know these forms and consider them in their whole constitution, not only by starting from the object, but also just as well by starting from the subject, because they are really the limits between object and subject which are common to them both; and he concluded that by following these limits we never penetrate to the inner nature either of the object or of the subject, consequently never know the true nature of the world, the thing in itself.
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