 During the periods just mentioned he was heavily occupied with the study and criticism of Kant’s philosophy. This work culminated in several unpublished essays—On the Highest Good (1789), On What Gives Value to Life (1792–3), and On Freedom (1790–3)—which rejected Kant’s conception that the “highest good [summum bonum]” requires an apportioning of happiness to moral desert, and Kant’s connected doctrine of the “postulates” of an afterlife of the soul and God, while also developing an anti-Kantian theory of the thoroughgoing causal determination of human action and of the compatibility of this with moral responsibility. In 1793–4 he wrote two essays about Spinoza: Spinozism and Brief Presentation of the Spinozistic System. A major catalyst for these essays was Jacobi’s work On the Doctrine of Spinoza, in Letters to Mr. Moses Mendelssohn (1785), which had been highly critical of Spinozism. But they also show the influence of Herder’s work God: Some Conversations (1787), which championed a modified form of Spinozism. In his two essays Schleiermacher himself embraces a modified form of Spinoza’s monism similar in character to Herder’s (in particular, like Herder, he is inclined to substitute for Spinoza’s single substance the more active principle of a single fundamental force). He also attempts to defend this position by showing it to be reconcilable with central features of Kant’s theoretical philosophy (notably, Kant’s doctrine of things in themselves). This neo-Spinozistic position (developed before Hölderlin’s in Judgment and Being or Novalis’ in Fichte-Studies, it should be noted) would subsequently be fundamental to Schleiermacher’s most important work in the philosophy of religion, On Religion: Speeches to Its Cultured Despisers (1799). However, in thus rejecting Jacobi’s anti-Spinozism, Schleiermacher seems also to have absorbed something from Jacobi that would be equally important for his future philosophy of religion: the idea (for which his pietist background no doubt made him receptive) that we enjoy a sort of immediate intuition or feeling of God.