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.
He did not deduce the thing in itself in the right way, as I shall show presently, but by means of an inconsistency, and he had to pay the penalty of this in frequent and irresistible attacks upon this important part of his teaching. He did not recognise the thing in itself directly in the will; but he made a great initial step towards this knowledge in that he explained the undeniable moral significance of human action as quite different from and not dependent upon the laws of the phenomenon, nor even explicable in accordance with them, but as something which touches the thing in itself directly: this is the second important point of view for estimating his services.
We may regard as the third the complete overthrow of the Scholastic philosophy, a name by which I wish here to denote generally the whole period beginning with Augustine, the Church Father, and ending just before Kant. For the chief characteristic of Scholasticism is, indeed, that which is very correctly stated by Tennemann, the guardianship of the prevailing national religion over philosophy, which had really nothing left for it to do but to prove and embellish the cardinal dogmas prescribed to it by religion. The Schoolmen proper, down to Suarez, confess this openly; the succeeding philosophers do it more unconsciously, or at least unavowedly. It is held that Scholastic philosophy only extends to about a hundred years before Descartes, and that then with him there begins an entirely new epoch of free investigation independent of all positive theological doctrine. Such investigation, however, is in fact not to be attributed to Descartes and his successors,1 but only an appearance of it, and in any case an effort after it. Descartes was a man of supreme ability, and if we take account of the age he lived in, he accomplished a great deal. But if we set aside this consideration and measure him with reference to the freeing of thought from all fetters and the commencement of a new period of untrammelled original investigation with which he is credited, we are obliged to find that with his doubt still wanting in true seriousness, and therefore surrendering so quickly and so entirely, he has, indeed, the appearance of wishing to throw off at once all the early implanted opinions belonging to his age and nation, but does so only apparently and for a moment, to assume them again immediately and hold them all the more firmly; and so is it with all his successors down to Kant. Goethe's lines are, therefore, very applicable to a free independent thinker of this kind:
Saving Thy gracious presence, he to me
A long-legged grasshopper appears to be,
That springing flies, and flying springs,
And in the grass the same old ditty sings.2
Kant had reasons for assuming the air of also intending nothing more. But the pretended spring, which was permitted because it was known that it leads back to the grass, this time became a flight, and now those who remain below can only look after him, and can never catch him again.
Kant, then, ventured to show by his teaching that all those dogmas which had been so often professedly proved were incapable of proof. Speculative theology, and the rational psychology connected with it, received from him their deathblow. Since then they have vanished from German philosophy, and one must not allow oneself to be misled by the fact that here and there the word is retained after the thing has been given up, or some wretched professor of philosophy has the fear of his master in view, and lets truth take care of itself. Only he who has observed the pernicious influence of these conceptions upon natural science, and upon philosophy in all, even the best writers of the seventeenth and eighteenth centuries, can estimate the extent of this service of Kant's. The change of tone and of metaphysical background which has appeared in German writing upon natural science since Kant is remarkable; before him it was in the same position as it still occupies in England. This merit of Kant's is connected with the fact that the unreflecting pursuit of the laws of the phenomenon, the elevation of these to the position of eternal truths, and thus the raising of the fleeting appearance to the position of the real being of the world, in short, realism undisturbed in its illusion by any reflection, had reigned throughout all preceding philosophy, ancient, mediæval, and modern. Berkeley, who, like Malebranche before him, recognised its one-sidedness, and indeed falseness, was unable to overthrow it, for his attack was confined to one point. Thus it was reserved for Kant to enable the idealistic point of view to obtain the ascendancy in Europe, at least in philosophy; the point of view which throughout all non-Mohammedan Asia, and indeed essentially, is that of religion. Before Kant, then, we were in time; now time is in us, and so on.