Reflections on Aristotle’s Modal Ontology

Abstract This chapter investigates the roles of Aristotle’s two newly coined ontological technical terms, entelecheia (‘completeness’) and energeia (‘at-workness’), and their connections with three traditional terms he inherited: dunamis (‘potentiality’), ergon (‘work’), and logos (‘account’). Through an analysis of passages in Metaphysics and De Anima, it argues that Aristotle introduces ‘completeness’ to refer to the substance of a thing—that is, the form (e.g., soul)—so that ‘form’, which signifies the causally basic unifying entity, and ‘completeness’, which signifies the governing mode of being one qua being, are employed in parallel in two contexts. In one, the form is identified and captured by means of a unified logos (account) called ‘definition’ that refers to completeness as a mode of being of ‘substance according to the account (ousia kata ton logon)’. In the other, the form is described as ‘substance as being at-work (tēn hōs energeian ousian)’, inherent in the relevant matter, which is not separate from the form in terms of work but is identified as potentiality in terms of account. It is argued, thus, that completeness is found in two contexts as (1) the governing mode of being of the form as a logos, in virtue of which (2) the agent, who is being in virtue of completeness, is at work by holding its governing mode for a certain duration of time.