One of the evident issues in Islamic philosophy is that epistemology is never dealt with separately and clearly, and this fact shows the necessity of research and counting the opinions of philosophers in this regard; Based on this, the current study is concerned with the development of the ontology of perceptual states, examining the different dimensions of the problem of the existence of perceptions and its gradual evolution, in the opinions of three philosophers who founded the school of Islamic philosophy, Ibn Sina, Suhrawardi, and Mulla Sadra. The principle in this research is the phenomenological approach in that it is investigated, what kind of perceptual states and characteristics the philosopher in question observes and counts under the phenomenon called perception when facing himself as an example of the human type. This phenomenal analysis of perception is placed in the framework of the metaphysical system of each philosopher and leads to his image of the criterion and his epistemic system. Since epistemology is always based on ontology, the development of the ontology of perceptual states occurs when the philosopher finds a fundamental difference in the foundations of existence and the phenomenal indicators of perception with the opinions of the philosopher before him. The slow transformation in the principles and indicators leads to the transformation in the explanation of the process of perception and evidence; Ibn Sina, based on his foundations, is committed to essentialism and the necessity of cognate unity, Suhrawardi goes through a part of them with the evolution of the foundations and explains the principle of illuminative relation, and Mulla Sadra emphasizes on his fundamentals. He criticizes some Suhrawardi'c claims and proposes his specific opinion. In this development, which is a kind of departure from the previous opinions, and as it advances, the role of the material world becomes less and the perception becomes more abstract, the soul is always the perceiver, but it has different explanations and it can be said that it is according to Ibn Sina's opinions act as a mirror to find perceptual states and represent them in themselves; In Suhrawardi, he acts like sight and as an eye observes the world and is based on the philosophy of Sadra, a re-creator who represents the outside world in the inside world.

Keywords: Perceptual states, Ontology of perceptual states, Avicenna, suhrawardi, MullaSadra.