The Status of Reason in the Scientific Methodology of Galen

Galen is one of the most prominent thinkers and scientists in antiquity, who paid special attention to the methodology of natural sciences. On the other hand, the transition of Galenic tradition to the Islamic world had a wide impact on different areas of thought, one of which was methodology. Accordingly, studying Galen's scientific methodology plays a significant role in a true understanding of the scientific tradition in the Islamic medieval ages. This article, using the method of text-oriented analytic interpretation, expounds on the status of reason as one of the two main elements of Galen's methodology. In his view, the reason is the main part of the human soul which provides the scientific method both formally and materially. Its formal functions, pertaining to the logical scope, are as follows: demonstration, division and synthesis, definition, similarity and dissimilarity, analysis and synthesis, and indication. On the other hand, in a material sense, the mind provides the necessary prerequisites for the formation of proof and implication by understanding rational axioms.