Reductive reasoning. The attempt to grasp what things are essentially inclines the old thinking to reason out a single ground for all beings, thereby reducing particular beings to something other than what they are. Our everyday experience confirms for us, Rosenzweig claims, the fundamental difference between divine, worldly, and personal beings. But over the course of the philosophical tradition, philosophers have repeatedly sought to reduce these three objects of special metaphysics one to the other, rather than to take each up as independent and irreducible. Thus ancient philosophy, by Rosenzweig’s account, tends to reduce the divine and the human to aspects of the cosmos; medieval philosophy reduces world and selfhood to aspects of the divine; and modern philosophy finds in the human self alone the firm ground upon which knowledge of all else is to be rooted.