 Aristotle, General Topics: metaphysics |  grounding, metaphysical |  identity: of indiscernibles |  Leibniz, Gottfried Wilhelm |  Leibniz, Gottfried Wilhelm: on causation |  Maimon, Salomon |  monism |  Schopenhauer, Arthur |  simplicity |  Spinoza, Baruch: modal metaphysics |  Wolff, Christian 