To know human soul has been thought in Islamic teachings to be a principle for knowing God. Sadr a-Din a-shirazi, from the 11th H., and Allamah Tabatabaei, from the 14th H., the former being the founder and the latter a deputy of the transcendental philosophy, have dominantly focused on the problem. Both philosophers, being of the same epistemological goal, differs in approach. For Sadra, human soul is the creator of idea and, therefore, an example for God, the real Creator. Allamah, however, knows it as an existentially depended being leading directly to the existence of its self-subsistent Creator.