Grasping the Quiddities

Aristotelian science consists in demonstrations from its first principles, the axioms and definitions. For Avicenna, like Aristotle, a definition gives ‘a formula of the essence’ or quiddity. Avicenna recognizes quiddities in three respects: in themselves, in re, and in intellectu. He grounds definitions on quiddities in themselves. Yet how are we to grasp these quiddities so as to get at the definitions? This chapter summarizes Avicenna’s threefold distinction of quiddity (triplex status naturae), as well as his recognition of both intelligible and perceptible individuals. It will then give an account of how Avicenna thinks that we can come to grasp quiddities in themselves.