Aristotle’s Fourfold Progression to Define the Soul

Aristotle introduces three soul-definitions in De Anima II.1: (i) ‘form definition’, (ii) ‘actualization definition’, and (iii) ‘instrument-based definition’. Drawing on insights from Parts of Animals I.5, this paper proposes a reconstructed fourth one: (iv) ‘telos definition’. Aristotle’s inquiry is progressive, meaning each new definition is intended to resolve the inadequacies of the previous one. His final proposal is that the soul is the principle of life as the final cause in a natural body. This definition conforms to the criteria for a causal definition as outlined in De Anima II.2 and Posterior Analytics II.