Galen was one of the most famous and well known ancient physicians who was also a philosopher, even though most of his philosophical writing is lost. Although, his philosophical interest also showed in his biological science works. Galen made famous anatomical observation in most of which was primates. Galen was very well-read and combined his works with very interesting techniques in observing practices to put more of light into teaching medicine. He often combines his observations with the philosophy of Plato and Aristotle. His role as one of the prominent and famous physicians in the medical world lasted for about one thousand years and he changed the way medicine was seen forever. Galen really observed and saw there is a method of difference