As the communal identity of opposites is the universal grounded, the ultimate ground must be identity as such. Now the simple unit appears.  It is outside our grasp but absolutely necessary (prop. 7, 1:395.4–6). The necessary existing unit is called “God” (ibid.). From it everything follows (prop. 8, 1:396.8–9). Specifically, what follows, and now once more within cognitive reach, is change (mutatio, 1:410.18). Kant’s Principle of Succession makes change intelligible: change occurs because of substantial connections ([substantiae] cum aliis connexae sunt); the mutual dependency of substances determines mutual alterations (prop. 12, 1:411.18–200). A bond governs change and thus reality. This dynamic-structural bond is a reciprocal, harmonious dependency. Metaphysical cognition ends with reciprocal commercium or interactivity, Kant’s Principle of Coexistence (prop. 13, 1:412–13).