Causality and its relation to the unity of existence according to Mullâ Ṡadrâ's view

The problem of causality and its relation to the unity of existence is one of the peculiar themes of Mulla Sadra (1571-1640). Although the treatment of and solutions to the problem of "causality" and the problem of "unity of existence" were considered by previous Islamic philosophers, no one considered these two problems could complement each other. Sadra, through the law of causality, proves the unity of existence. The applications of Sadra's principles (of the fundamental reality of existence and the analogical gradation of existence) which are the central principles of his entire thought, provide his unique theory of "unity of existence." By this theory he attempted to convince mystics that although there is in the world one reality, that reality manifests itself in various degrees of classifications and intensity of existence