Friedrich Heinrich Jacobi (; German: [jaˈkoːbi]; 25 January 1743 – 10 March 1819) was a German philosopher, writer and socialite. He is best known for popularizing the concept of nihilism, denigrating it as the necessary result of Enlightenment thought and the philosophical systems of Baruch Spinoza, Immanuel Kant, Johann Gottlieb Fichte and Friedrich Wilhelm Joseph Schelling.
Jacobi advocated Glaube (variously translated as faith or "belief") and Offenbarung (revelation) instead of speculative reason. According to one view, Jacobi can be seen to have anticipated present-day writers who criticize secular philosophy as relativistic and dangerous for religious faith. His aloofness from the Sturm and Drang movement was the basis of a brief friendship with Johann Wolfgang von Goethe.
He was the younger brother of poet Johann Georg Jacobi and the father of the psychiatrist Maximilian Jacobi.
He was born at Düsseldorf, the second son of a wealthy sugar merchant, and was educated for a commercial career, which included a brief apprenticeship at a merchant house in Frankfurt-am-Main during 1759. Following, he was sent to Geneva for general education. Jacobi, of a retiring, meditative disposition, associated himself at Geneva mainly with the literary and scientific circle (of which the most prominent member was Georges-Louis Le Sage).
He studied closely the works of Charles Bonnet, as well as the political ideas of Jean-Jacques Rousseau and Voltaire. In 1763, he was recalled to Düsseldorf, and in the following year, he married Elisabeth von Clermont and took over the management of his father's business.
After a short time, he gave up his commercial career, and in 1770, he became a member of the council for the duchies of Jülich and Berg. He distinguished himself by his ability in financial affairs and his zeal in social reform. Jacobi kept up his interest in literary and philosophical matters through an extensive correspondence. His mansion at Pempelfort, near Düsseldorf, was the centre of a distinguished literary circle. He helped to found a new literary journal with Christoph Martin Wieland. Some of his earliest writings, mainly on practical or economic subjects, were published in Der Teutsche Merkur.
Here too appeared in part the first of his philosophical works, Edward Allwill's Briefsammlung (1776), a combination of romance and speculation. This was followed in 1779 by Woldemar, a philosophical novel, of very imperfect structure, but full of genial ideas, and giving the most complete picture of Jacobi's method of philosophizing.
In 1779, he visited Munich following his appointment as minister and privy councillor for the Bavarian department of customs and commerce. He opposed the mercantilistic policies of Bavaria and intended to liberalize local customs and taxes; but, after a short stay there, differences with his colleagues and with the authorities of Bavaria, as well as his unwillingness to engage in a power struggle, drove him back to Pempelfort. The experience as well as its aftermath led to the publication of two essays in which Jacobi defended Adam Smith's theories of political economy. These essays were followed in 1785 by the work which first brought Jacobi into prominence as a philosopher.
A conversation with Gotthold Lessing in 1780 in which Lessing avowed that he knew no philosophy in the true sense of that word, save Spinozism, led him to a protracted study of Spinoza's works. After Lessing's death, just a couple of months later, Jacobi continued to engage with Spinozism in an exchange of letters with Lessing's close friend Moses Mendelssohn, which began in 1783. These letters, published with commentary by Jacobi as Briefe über die Lehre Spinozas (1785; 2nd ed., much enlarged and with important Appendices, 1789), expressed sharply and clearly Jacobi's strenuous objection to a dogmatic system in philosophy, and drew upon him the vigorous enmity of the Aufklärer.
Jacobi was ridiculed for trying to reintroduce into philosophy the antiquated notion of unreasoning belief, was denounced as an enemy of reason, as a pietist, and as a Jesuit in disguise, and was especially attacked for his use of the ambiguous term "belief". His next important work, David Hume on Faith, or Idealism and Realism (David Hume über den Glauben oder Idealismus und Realismus, 1787), was an attempt to show not only that the term Glaube had been used by the most eminent writers to denote what he had employed it for in the Letters on Spinoza, but that the nature of the cognition of facts as opposed to the construction of inferences could not be otherwise expressed. In this writing, and especially in the Appendix, Jacobi came into contact with the critical philosophy and subjected the Kantian view of knowledge to searching examination. Jacobi addressed in the said Appendix Kant's concept of "thing-in-itself." Jacobi agreed that the objective thing-in-itself cannot be directly known. However, he stated, it must be taken on faith. A subject must believe that there is a real object in the external world that is related to the representation or mental idea that is directly known. This faith or belief is a result of revelation or immediately known, but logically unproven, truth. The real existence of a thing-in-itself is revealed or disclosed to the observing subject. In this way, the subject directly knows the ideal, subjective representations that appear in the mind, and strongly believes in the real, objective thing-in-itself that exists outside of the mind. By presenting the external world as an object of faith, Jacobi legitimized belief and its theological associations. Schopenhauer would later state: "…[B]y reducing the external world to a matter of faith, he wanted merely to open a little door for faith in general…."
Ironically, the pantheism controversy led later German philosophers and writers to take an interest in pantheism and Spinozism. Jacobi's fideism remained unpopular, and instead his critique of Enlightenment rationalism led more German philosophers to explore atheism and wrestle with the perceived loss of philosophical foundations for theism, myth, and morality. Jacobi and the pantheism controversy he ignited remain important in European intellectual history, because he formulated (albeit critically) one of the first systematic statements of nihilism and represents an early example of the death of God discourse.
The Pempelfort era came to an end in 1794 when the French Revolution spilled over into Germany following the outbreak of war with the French Republic. The occupation of Düsseldorf by French troops forced him to resettle and, for nearly ten years, live in Holstein. There he became intimately acquainted with Karl Leonhard Reinhold (in whose Beyträge zur leichtern Uebersicht des Zustandes der Philosophie beym Anfange des 19. Jahrhunderts Jacobi's important work, "Ueber das Unternehmen des Kriticismus, die Vernunft zu Verstande zu bringen", was first published), and with Matthias Claudius, the editor of the Wandsbecker Bote.
Gottlieb Fichte was dismissed from Jena in 1799 as a result of a charge of atheism. He was accused of this in 1798, after publishing his essay "Ueber den Grund unsers Glaubens an eine göttliche Weltregierung" ("On the Ground of Our Belief in a Divine World-Governance"), which he had written in response to Friedrich Karl Forberg's essay "Development of the Concept of Religion", in his Philosophical Journal. For Fichte, God should be conceived primarily in moral terms: "The living and efficaciously acting moral order is itself God. We require no other God, nor can we grasp any other" ("On the Ground of Our Belief in a Divine World-Governance"). Fichte's intemperate "Appeal to the Public" ("Appellation an das Publikum", 1799) as well as a more thoughtful response entitled “From a Private Letter” (1799), provoked F. H. Jacobi to publish Letter to Fichte (1799), in which he equated philosophy in general and Fichte's transcendental philosophy in particular with nihilism and the relation of his own philosophical principles to theology.