The Identity of Subject and Object from the Viewpoint of Mullā Ṣadrā and Ibn Sīnā

The identity (ittiḥād or unification) of subject and object is an attempt in elucidating the manner of relation between the knowledge and the knower and the quality of perception by means of which the known problems concerning mental existence are removed. With the acceptance of this theory the problem of a single object as being substance and accident and the applicability of two subjects to one object, which according to Ḥakīm Sabzevari has bewildered intellects, would not be addressed. In theory of identity, Mullā Ṣadrā claims that every intelligible existence is intelligent too; furthermore, if it is achieved in human rational soul, whether intelligible or sensible, it is one with its percipient. The identity that Ibn Sīnā has argued on its invalidity is related to the two existents that potentially exist and are actualized in their accident before unification (and the contradiction of the two is real, not a rational analysis). Ṣadrā does not regard as acceptable such an identity for the same reasons that Ibn Sīnā has stated.
In the identity of subject and object, philosophers are divided upon the knowledge of the soul of the other, while all agree that each abstract object persisting in its essence is intellect, subject, and object in relation to itself. None of the Muslim philosophers denies unity in the knowledge of the abstract of its essence because in this case there is no mental image so that it is accident to the soul and not its object. What is doubtful in this discourse relates to the perception of another. In fact, there is a substance here that is in one sense subject, in another sense intellect, and yet in another sense object. Actually, here it is unity not identity.