Galen’s Theory of the Soul

This paper aims to explain Galen’s theory of the soul in the context of medicine and philosophy during the Hellenistic and Roman periods. Analyzing various related texts, we will get the following conclusions: ① Galen inherited and developed the neuroanatomy of Herophilus and Erasistratus. While they were interested in basic bodily functions such as nutrition, digestion etc., they didn’t answer the question how the soul interacts with the body. Galen, on the contrary, explained in detail the relation between the soul and the body, because he thought that the body and the soul interact mutually. According to Galen, our bodily mixtures and pneuma can change as a result of environment and life style. So it is up to us to manage and maintain our physical and psychological health. ② Although Galen was influenced by Plato’s philosophy, he did not accept uncritically Plato’s view. Galen accepted only the empirically observable facts that are useful both for medicine and for ethical and political philosophy, while he withheld judgment on metaphysical hypotheses such as the substance of God or the soul. He tried to reinterpret and develop physiologically Plato’s tripartite theory of the soul. ③ Gill contends that Galen had better adopt the Stoic unified theory of the soul rather than Plato’s tripartite account. According to Gill, outside of De placitis Hippocratis et Platonis, Galen’s brain-centered psycho-psysiology is consistent with the Stoic view. But in opposition to Gill’s interpretation, Galen’s De moribus says that three parts of the soul sometimes collaborate with each other, sometimes conflict with each other. Gallen thinks that pneuma(or neura) is a medium through which the three parts of the soul communicate and cooperate with each other. Therefore, the body and the soul function properly, when the three parts do their own job in harmony with each other.