Trying to understand the reality of the soul and its result (Self Knowledge Theology) has always attracted philosophers’ attention and has been regarded as one of the concerns of philosophical thinking. In this article, it is specified that the peripatetic philosophers, whether Greek or Islamic, have considered the soul as a chapter of naturalia and try mostly to comment on the soul’s powers and activities; they have not had any epistemological view of it. In contrast, Sheikh Eshragh closes the psychology to the theological discussions and looks at it from the epistemological point of view. His discussion is not about soul’s powers, but he provides a way to save the soul from the prison of the body and emancipate the human being from the darkness of material world. In the illuminationist philosophy, the theory of intuition was proposed for the first time (The substantial form), so it has discussed the nature of the soul from this viewpoint. Suhrawardi’s psychology isn’t a consequence of theoretical discussion, but it results from introspection and self-awareness that is possible only through the asceticism and controlling the dragon of carnal soul. It is soul which shows not only the Light of Lights, but it becomes divine and finally through this path he founds his luminous system. The system of being is realized through the epistemology of soul.