Other traditions hold that he starved himself to death, others tell that he was suffocated or thrown from the wall of the fortress, then burned. Arising out of peripatetic philosophy as developed by Ibn Sina (Avicenna), Suhrawardi's illuminationist philosophy is critical of several of Ibn Sina's positions and radically departs from him in creating a symbolic language (mainly derived from ancient Iranian culture or "Farhang-e Khosravani") to give expression to his wisdom ("hikma"). Suhrawardi taught a complex and profound emanationist cosmology, in which all creation is a successive outflow from the original Supreme Light of Lights ("Nur al-Anwar"). The fundamental of his philosophy is pure immaterial light, where nothing is manifest, and which unfolds from the Light of Lights in a descending order of ever-diminishing intensity and, through complex interaction, gives rise to a "horizontal" array of lights, similar in conception to Platonic forms, that governs mundane reality. In other words, the universe and all levels of existence are but varying degrees of Light—light and darkness. In his division of bodies, he categorizes objects in terms of their reception or non-reception of light. Suhrawardi considers a previous existence for every soul in the angelic realm before its descent to the realm of the body. The soul is divided into two parts, one remains in heaven and the other descends into the dungeon of the body. The human soul is always sad because it has been divorced from its other half. Therefore, it aspires to become reunited with it. The soul can only reach felicity again when it is united with its celestial part, which has remained in heaven. He holds that the soul should seek felicity by detaching itself from its tenebrous body and worldly matters and access the world of immaterial lights. The souls of the gnostics and saints, after leaving the body, ascend even above the angelic world to enjoy proximity to the Supreme Light, which is the only absolute Reality. Suhrawardi elaborated the neo-Platonic idea of an independent intermediary world, the imaginal world ("ʿalam-i mithal" عالم مثال). His views have exerted a powerful influence down to this day, particularly through Mulla Sadra’s combined peripatetic and illuminationist description of reality. Suhrawardi's Illuminationist project was to have far-reaching consequences for Islamic philosophy in Shi'ite Iran.