The influence of philosophical teachings on Galen's knowledge of physiology

Every science is based on metaphysical and philosophical assumptions, and medicine is no exception. In mixed medicine, Galen considers philosophy and logic to be part of medicine and bases his medical theory on it. Therefore, Galen considered anatomy and physiology not only for the study of organs and processes inside the body, but also as an important source for answering philosophical questions.Therefore, the problem of the present research is to investigate the impact of Galen's philosophical teachings on his knowledge of anatomy and physiology. For this purpose, the article consists of four parts: in the first part, the history of physiology before Galen is examined, and in the second part, it deals with the philosophical teachings and important concepts of the knowledge of physiology and Galen's philosophical outlook, and in the next parts, the impact of Galen's philosophical teachings on the knowledge of the physiology of the brain and nerves. Cardiology, respiration, digestion, reproduction and embryology are examined. This research has been carried out by library method and relying on the works attributed to Galen. Examining the works related to Galen's physiology shows that he was influenced by Plato's theory of the three organs and believed that the three main organs of the body are the brain, heart and liver, therefore Galen's system of physiology includes a set of activities focused on the liver, heart/lungs and brain. A process that must be constantly renewed to continue living. Also, Galen's goal of analyzing and understanding the anatomy and physiology of the body was to understand the nature of pneuma.