Doctrine propounded by the Persian philosopher and mystic Suhrawardi (1154–91) in The Philosophy of Illumination (1186). Knowledge, like vision, consists in the unveiled presence of the object of knowledge before the self-aware knower; with suitable training, we can apprehend immaterial beings such as angels and Platonic forms (and God). Light is the most self-aware of entities, ‘that which is manifest in itself and manifests others’. Self-subsistent or immaterial lights are identified with intellects or minds; anything that is alive must be an immaterial light (self-aware and aware of other things, like a Leibnizian monad). God at the top of the tree, is the Light of Lights, an immaterial light not caused by another immaterial light. A popularized form of Suhrawardi's philosophy enjoyed a vogue in India in the shape of a forged Persian scripture, the Dasatir, thought by many Zoroastrian scholars to be the lost secret wisdom of the Zoroastrian sages.