ABSTRACT
This chapter examines the dialogue between Severus of Antioch, a critic of the Chalcedonian definition of the two natures in Christ, and Leontius of Byzantium, who applied the logic of Aristotle, as mediated by Porphyry, to the Chalcedonian formula. After a close study of the use of key terms such as phusis and ousia in both authors, it will be argued that Leontius avoided the charge of “Nestorianism” (i.e. of affirming two Christs) by assigning different principles of individuation to divine and human nature.
