(2.) Yet Jacobi essentially agrees with Kant’s critick of the understanding. Jacobi affirmed, as Kant had done, that the understanding is insufficient to know the supersensible, and that the highest ideas of the reason could be apprehended only in faith. Jacobi places Kant’s great merit in having cleared away the ideas, which were simply the products of reflection and logical phantasms. “It is very easy for the understanding, when producing one notion from another, and thus gradually mounting up to ideas, to imagine that, by virtue of these, which, though they carry it beyond the intuitions of the sense, are nothing but logical phantasms, it has not only the faculty but the most decided determination to fly truly above the world of sense, and to gain by its flight a higher science independent of the intuition, a science of the supersensible. Kant discovers and destroys this error and self-deception. Thus there is gained, at least, a clear place for a _genuine_ rationalism. This is Kant’s truly great deed, his immortal merit. But the sound sense of our sage did not allow him to hide from himself that this clear place must disappear in a gulf, which would swallow up in itself all knowledge of the true, unless a God should interpose to hinder it. Here Kant’s doctrine and mine meet.”
(3.) But Jacobi does not fully agree with Kant, in wholly denying to the theoretical reason the faculty of objective knowledge. He blames Kant for complaining that the human reason cannot theoretically prove the reality of its ideas. He affirms that Kant is thus still entangled in the delusion, that the only reason why these ideas cannot be proved, is found in the nature of the ideas themselves, and not in the deficient nature of our knowledge. Kant therefore attempts to seek, in a practical way, a kind of scientific proof; a roundabout way, which, to every profound seeker, must seem folly, since every proof is as impossible as it is unnecessary.
Jacobi agreed better with Kant, than with the post-Kantian philosophy. The atheistic tendency of the latter was especially repulsive to him. “To Kant, that profound thinker and upright philosopher, the words God, freedom, immortality, and religion, signified the same as they have ever done to the sound human understanding; he in no way treats them as nothing but deception. He created offence by irresistibly showing the insufficiency of all proofs of speculative philosophy for these ideas. That which was wanting in the theoretical proof, he made up by the necessary postulates of a pure practical reason. With these, according to Kant’s assurance, philosophy was fully helped out of her difficulty, and the goal, which had been always missed, actually reached. But the first daughter of the critical philosophy (Fichte’s system) makes the living and working moral order itself to be God, a God expressly declared to be without consciousness and self-existence. These frank words, spoken publicly and without restraint, roused some attention, but the fear soon subsided. Presently astonishment ceased wholly, for the second daughter of the critical philosophy (Schelling’s system) gave up entirely the distinction which the first had allowed to remain between natural and moral philosophy, necessity and freedom, and without any further ado affirmed that the only existence is nature, and that there is nothing above; this second daughter is Spinozism transfigured and reversed, an ideal materialism.” This latter allusion to Schelling, connected as it was with other and harder thrusts in the same essay, called out from this philosopher the well-known answer: “_Schelling’s Monument to the Treatise on Divine Things_, 1812.”