Sadr-ul-Muta 'allehin, a prominent figure among Islamic philosophers spent his utmost efforts to connect Islamic philosophy, !ysticism, theology and exegesis of Hojy Qur'an in some of the dijferent discussions such as the Primary and Unit» of the Truth of Being (Esalat va Vahdat-e Haqiqat-e Vojoud), the relationship of causaliry which he has defined as actualization (Tasha'on), analogicalgradation of being (T.ashkik-e Vqjoud) , transubstantiation (Harekat-e Johan), the uniry of the Intelligence and the Intelligible (Ettehad-e 'Aghel va Ma 'ghou, and the immaterialiry of the faculry of imagination (tajarrod-e khia01 and Platonic Ideas. He interpreted the meaning of Platonic Ideas on one qf the mystical theories, i.e. ''immutable essences" (A 'ayan-e Sahetah). The present article elaborates dijferent viewpoints among the Islamic philosophers and the critiques of Sadr-ul-Muta1allehin of their perceptions such as Farabi, Ibn-e Sina (Avicenna), Suhra1vardi1 Dauani, and Mirdamad, and commenting on interpretation of Mulla Sadra and also plans to reviews his eight neu. proofs ofPlatonic Ideas.