Friedrich Heinrich Jacobi (1743-1819) gave the most detailed statement of the position of the philosophy of feeling, and the most careful proof of it. He was born in Düsseldorf, the son of a manufacturer; until 1794 he lived in his native place and at his country residence in Pempelfort; later he resided in Holstein, and, from 1805, in Munich, where, in 1807-13, he was president of the Academy of Sciences. Of his works, collected in five volumes, 1812-25, we are here chiefly concerned with the letters _On the Doctrine of Spinoza_, 1785; _David Hume on Faith, or Idealism and Realism_, 1787; and the treatise _On Divine Things_, 1811, which called out Schelling's merciless response, _Memorial of Jacobi_. Besides Hume and Spinoza, the sensationalism of Bonnet and the criticism of Kant had made the most lasting impression on Jacobi. His relation to Kant is neither that of an opponent nor of a supporter and popularizer. He declares himself in accord with Kant's critique of the understanding (the understanding is merely a formal function, one which forms and combines concepts only, but does not guarantee reality, one to which the material of thought must be given from elsewhere and for which the suprasensible remains unattainable); in regard to the critique of reason he raises the objection that it; makes the Ideas mere postulates, which possess no guarantee for their reality. The critique of sensibility appears to him still more unsatisfactory, as it does not explain the origin of sensations. Without the concept of the "thing-in-itself" one cannot enter the Kantian philosophy, and with it one cannot remain there. Fichte has drawn the correct conclusion from the Kantian premises; idealism is the unavoidable result of the Critique of Reason and foretold by; it as the Messiah was foretold by John the Baptist. And by the evil fruit we know the evil root: the idealistic theory is philosophical nihilism, for it denies the reality of the external world, as the materialism of Spinoza denies a transcendent God and the freedom of the will. Reality slips away from both these systems--they are the only consistent ones there are--material reality escaping from the former and suprasensible reality from the latter; and this must be so, because reality, of whatever kind it be, cannot be known, but only believed and felt. The actual, the existence of the noumenal as well as of the external world, even the existence of our own body, makes itself known to us through revelation alone; the understanding comprehends relations only; the certainty that a thing exists is attained only through experience and faith. Sense and reason are the organs of faith, and hence the true sources of knowledge; the former apprehends the natural, the latter, the supernatural, while for the understanding is left only the analysis and combination of given intuitions.