 The source of Schelling’s concern with Spinoza is the ‘Pantheism controversy’, which brought Spinoza’s monism into the mainstream of German philosophy. In 1783 the writer and philosopher F.H. Jacobi became involved in an influential dispute with the Berlin Enlightenment philosopher Moses Mendelssohn over the claim that G.E. Lessing had admitted to being a Spinozist, an admission which at that time was tantamount to the admission of atheism, with all the dangerous political and other consequences that entailed. In his On the Doctrine of Spinoza in Letters to Herr Moses Mendelssohn, (1785, second edition 1789), which was influenced by his reading of Kant’s first Critique, Jacobi revealed a problem which would recur in differing ways throughout Schelling’s work. Jacobi’s interpretation of Spinozism was concerned with the relationship between the ‘unconditioned’ and the ‘conditioned’, between God as the ground of which the laws of nature are the consequent, and the linked chains of the deterministic laws of nature. Cognitive explanation relies, as Kant claimed, upon finding a thing’s ‘condition’. Jacobi’s question is how finding a thing’s condition can finally ground its explanation, given that each explanation leads to a regress in which each condition depends upon another condition ad infinitum. Any philosophical system that would ground the explanation of a part of nature thus “necessarily ends by having to discover conditions of the unconditioned” (Scholz, ed., 1916, p. 51). For Jacobi this led to the need for a theological leap of faith, as the world’s intelligibility otherwise threatened to become a mere illusion, in which nothing would be finally grounded at all. In the 1787 Introduction to the first Critique Kant maintains this problem of cognitive grounding can be overcome by acknowledging that, while reason must postulate the “unconditioned (…) in all things in themselves for everything conditioned, so that the series of conditions should thus become complete” (Kant, Critique of Pure Reason B, p. XX), by restricting knowledge to appearances, rather than assuming it to be of “things in themselves”, the contradiction of seeking conditions of the unconditioned can be avoided. As we have already seen, though, this gives rise precisely to the problem of how a subject which is not conditioned like the nature it comes to know can emerge as the ground of knowledge from deterministic nature.