Über die Lehre des Spinoza, in Briefen an den Herrn Moses Mendelssohn

Friedrich Heinrich Jacobi's work, Über die Lehre des Spinoza, in Briefen an den Herrn Moses Mendelssohn (1785), is a critique of rationalism, particularly as espoused by Benedict de Spinoza. Jacobi, a proponent of the philosophy of feeling (Gefühlsphilosophie), found Spinoza's purely rationalistic approach to be objectionable.1

In this work, Jacobi argues against the idea that all truths can be derived solely through reason. He posits that belief, which includes not only the reality of sensory experience but also truths of the heart and spirit, is immediate and should not be subjected to rigorous mental processes. Jacobi's ideas were part of a broader intellectual current in the German Enlightenment, where thinkers like Moses Mendelssohn were also engaging with philosophical questions concerning Judaism and reason. Jacobi's work challenged the prevailing rationalist views of his time, emphasizing the importance of intuition and faith.12