Jiva Goswami
It was in his Sarva-samvadini commentary to the Sat Sandarbhas of Hindu philosophy that Jiva Goswami first wrote of Achintya Bheda Abheda, the philosophy of Chaitanya Mahaprabhu. In essence, the philosophy of Achintya bheda abheda, or "inconceivable oneness and difference", avoids the extremes of Shankara's monistic Advaita vedanta and Madhva's pure dualism (Dvaita) by interpreting the material and spiritual potencies of the Supreme Person (Bhagavan) as being simultaneously one and different with Him.