«Ontology» has never been only a scene of watching and consequently a field of describing and explaining for Islamic philosophers and sages. In another for them words «ontology»was not confined, in seeing and understanding, but they considered becoming and going as a part of ontology.«Theosophy», in the glossary of Islamic philosophy, often indicates to this side of ontology. Today this kind of ontology is proposed under the name of ontological approach and understanding in the theistic and atheistic branches of existentialistic philosophies and is used for evaluating abstract thinking about ontology. This kind of approach to ontology is particularly interesting and worthy of contemplation from view point of divine sages. Such as Mulla Sadra. In this paper we try to have a glance to this kind of viewing.