Christian August Crusius

Christian August Crusius (10 January 1715 – 18 October 1775) was a German philosopher and Protestant theologian. Born in Leuna, Electorate of Saxony, he was educated at the University of Leipzig. Crusius became an extraordinary professor of theology there in 1744, an ordinary professor in 1750, and a senior university officer in 1773. He also served as president of the university in 1755 and 1767. Crusius gained recognition as an opponent of Gottfried Leibniz and Christian Wolff's philosophies, particularly from the perspective of religious orthodoxy. He argued against determinism, emphasizing the moral evils that could arise from it, and sought to defend the concept of free will. His significant works from this period include 'Anweisung, vernünftig zu leben' (1744), 'Entwurf der nothwendigen Vernunftwahrheiten...' (1745), 'Weg zur Gewissheit und Zuverlässigkeit der menschlichen Erkenntniss' (1747), and 'Anleitung, über natürliche Begebenheiten ordentlich und vorsichtig nachzudenken' (1749). Although his philosophical books enjoyed a considerable but brief popularity, his critique of Wolff notably influenced Immanuel Kant during the formation of his philosophical system. Kant's doctoral thesis and 'Critique of Practical Reason' cite Crusius's ethical and epistemological doctrines. Kant himself acknowledged being 'deeply influenced by Crusius' but also refuted certain aspects of his thought in 'Prolegomena to Any Future Metaphysics'. Later in his career, Crusius dedicated himself to theology, leading the 'Crusianer' faction at the university against the 'Ernestianer' followers of Johann August Ernesti. This divergence stemmed from their differing approaches to exegesis, with Ernesti advocating for treating Scripture like other ancient texts and Crusius adhering to orthodox ecclesiastical tradition. He died in Leipzig.