 He accepted the Stoic categorization of philosophy into physics (natural philosophy, including metaphysics and theology), logic (including dialectic), and ethics.These three categories for him were, in Stoic fashion, inseparable and interdependent parts of an organic, natural whole.He compared them to a living being, with physics the meat and blood, logic the bones and tendons holding the organism together, and finally ethics – the most important part – corresponding to the soul.