Jacobi had the clearest consciousness of the opposition in which he stood, with this principle of immediate knowledge, to previous philosophy. In his introduction to his complete works, he says: “There had arisen since the time of Aristotle an increasing effort in philosophical schools, to subject the immediate knowledge to the mediate, to make that faculty of perception which originally establishes every thing, dependent on the faculty of reflection, which is conditioned through abstraction; to subordinate the archetype to the copy, the essence to the word, the reason to the understanding, and, in fact, to make the former wholly disappear in the latter. Nothing is allowed to be true which is not capable of a double demonstration, in the intuition and in the conception, in the thing and in its image or word; the thing itself, it is said, must truly lie and actually be known only in the word.” But every philosophy which allows only the reflecting reason, must lose itself at length in an utter ignorance. Its end is nihilism. 3. From what has been already said, the position of Jacobi with his principle of faith, in relation to the Kantian philosophy, can, partly at least, be seen. Jacobi had separated himself from this philosophy, partly in the above-named dialogue “David Hume,” (especially in an appendix to this, in which he discussed the transcendental Idealism), and partly in his essay “_On the attempt of criticism to bring the reason to the understanding_” (1801). His relation to it may be reduced to the following three general points: (1.) Jacobi does not agree with Kant’s theory of sensuous knowledge. In opposition to this theory he defends the standpoint of empiricism, affirms the truthfulness of the sense-perception, and denies the apriority of space and time, for which Kant contends in order to prove that objects as well as their relations are simply determinations of our own self, and do not at all exist externally to us. For, however much it may be affirmed that there is something corresponding to our notions as their cause, yet does it remain concealed what this something is. According to Kant, the laws of our beholding and thinking are without objective validity, our knowledge has no objective significance. But it is wrong to claim that in the phenomena there is nothing revealed of the hidden truth which lies behind them. With such a claim, it were far better to give up completely the unknown thing-in-itself, and carry out to its results the consequent idealism. “Logically, Kant is at fault, when he presupposes objects which make impressions on our soul. He is bound to teach the strictest idealism.”