 Out of the interaction of the irradiations of the vertical and the horizontal lights, the bodies of the lower world are generated. These two hierarchies of lights are structurally interrelated through the principle domination (qahr) that the higher lights have over the lower ones and the principle of desire and love (mahabba) that the lower lights have for the higher lights (PI, §§152–6). The increase of dominating immaterial lights and the introduction of a second order of horizontal lights (the Platonic Forms) enabled the possibility of simple effects from composite causes (PI, §§94–5). The two dimensional hierarchy of lights introduces a new nonlinear and composite notion of metaphysical causation. The multiplication of metaphysical entities increases the ontological distance that exists between the Light of Lights and the sublunar world, while simultaneously providing a greater holistic view of reality, since light lies at its core. Notions of intensity and gradation of light, together with notions of presence and self-manifestation, are thus central to Suhrawardi’s metaphysics. The intensity of light corresponds to the degree of the lights self-awareness. Similarly, the self-awareness of the Light of Lights encompasses, with varying degrees of intensity, all the other constitutive lights of reality. Later, Mulla Sadra (d.1636) will take up Suhrawardi’s insight about the gradation and intensity of light and develop an ontology grounded in the gradation of existence (rather than light) of all beings, somehow reversing Suhrawardi’s ontology with his primacy of existence and his understanding of essence as a mental concept. 