Mullah Sadra (ملاصدرا) revolutionized the metaphysics of being, in reversing the order of priority of essence (mahiat ماهیت). he gives priority to existence (vojud وجود): that means, it is the act and mode of existing that determine the nature of essence. the act of existing is in effect capable of multitude of degrees of intensification or of degradation.

being, Corbin, essence, existence, existing, metamorphosis, metaphysic, palingeneses, phenomenology, Sadra,

Mullah Sadra is the philosopher of metamorphoses and palingeneses (estehaleh-ha & rastakhiz-ha [استحاله ها و رستاخیزها])
*phenomenology of the act of existing*