Friedrich Heinrich Jacobi (1743-1819), a German philosopher of the Enlightenment, emphasized the philosophic dimensions of feeling and faith in opposition to the claims of pure reason.

On Jan. 25, 1743, F. H. Jacobi was born in Düsseldorf, the son of a wealthy sugar manufacturer. He prepared at Geneva for a business career and succeeded his father as head of the firm from 1764 to 1772. Friedrich retired in favor of a political career, first as a member of the governing council of two duchies and eventually as privy counselor to the Bavarian court. His household became an important center of German literature.

With his older brother, Johann Georg (1740-1814), a well-known romantic poet, Jacobi edited a journal and wrote several philosophical novels inspired by his studies of Jean Jacques Rousseau, C. A. Helvétius, and the 3d Earl of Shaftesbury. Jacobi's activities brought him into personal and literary contact with most of the central thinkers and writers of the German Enlightenment, including Gotthold Ephraim Lessing, Moses Mendelssohn, and J. W. von Goethe. In 1804 he became president of the Academy of Sciences in Munich, where he remained until his death on March 10, 1819.

The point of departure for Jacobi's thought is the antinomy, or seeming contradiction, between realism and idealism. Baruch Spinoza was a dogmatic realist who drew out the logical consequences of the traditional definition of substance as that which is the cause of itself. According to this view, there could be only one substance, an infinite eternal being of which the world of nature is only a partial but determinate modification. The meaning of Spinoza's pantheism, or the identification of God with nature, was a subject of other disputes throughout the 19th century. Jacobi sided with those who thought that Spinoza was, in fact, an atheist who had reduced God to a logical, mathematical, and mechanistic concept of nature. Other writers and philosophers such as Johann Georg Hamann, Johann Gottfried von Herder, Lessing, and Mendelssohn held that Spinoza was the first religious thinker to seriously develop the philosophic dimensions of the concept of an infinite being. Largely through Jacobi's instigation the major figures of the Enlightenment produced an extensive literature of books, inquiries, and couterinquiries about Spinoza.

Jacobi saw in Spinoza the elimination of real subjectivity and in the philosophy of Immanuel Kant an opposite "nihilism of objects." Kant was the first to raise the critical question of how subjective consciousness arrives at a knowledge of things, and he concluded that ultimately we can know of things "only what we have placed in them." Thus for Kant, human experience is simply the appearance of the way things seem and are thought about according to the subjective conditions of the mind. Objects as things-in-themselves are unknowable.

The point of these criticisms was to show that if reason begins with objects it is unable to account for subjectivity and a subjective perspective annihilates objectivity. The conclusion which Jacobi drew was that the enterprise of human reason itself rests on faith. Man's immediate certainty that there are real objects, which produce passive sensations, rests on faith. And if the concept of objective nature depends on faith, then man's feelings and intuitions of freedom, moral principles, and religious certainties need not defer to rational skepticism.

Further Reading

• Friedrich Heinrich Jacobis Werke, 6 vols. (1812-1825), has never been translated. The only secondary source available in English is Alexander W. Crawford, The Philosophy of F. H. Jacobi (1905). For general background see Frederick J. Copleston, A History of Philosophy, vol. 6: Wolff to Kant (1964).
• Hegel, Georg Wilhelm Friedrich, Faith & knowledge, Albany, NY: State University of New York Press, 1977.