Perception and the study of its different aspects throughout the history has been among the challenging topics in philosophy. One of the expressions of this subject is the perception of the self; the statment of the problem is as follows: How is it that an existent can perceive itself?
Peripatetics believe that every existent abstracted from matter is the knower of its self; on the contrary, from Shaykh al-Ishraq’s point of view the only existent that can be the knower of its essence is the light by itself. Shaykh al-Ishraq states that by assuming the acceptance of peripatetic theory, it is necessary that prime matter be knower of itself and all self-subsistent forms and gives the prime matter having no quiddity like necessary being be the knower of all things and on the other hand necessary being too like prime be in need of forms. Of course Suhravardi regards all these consequences as invalid.
In defence of the peripatetic theory as an agreeable theory the objections of Shaykh al-Ishraq are rejected and the origin of it is traced back to the weakness of Shaykh in Understanding the remarks of the peripatetics, because peripatetics do not reqard the abstract prime matter being actualised in outside world (rather they consider the prime matter as mere potency that has no independent actuality in outside world a part from its form) and in a same manner they do not believe that prime matter is a mere existence and without essence (like God), in consequence, the objections of Shaykh al-Ishraq are not valid.