Abstract

This dissertation is a study of the evolution of the concept of energeia from its origins in Aristotle to its adaptations in Neoplatonism. The term energeia is formed from the verb energeia, "to be active or effective, to operate." In his earliest works Aristotle uses it to indicate the active exercise of a faculty as opposed to mere possession of that faculty. From this beginning the word took on two fundamental senses: activity and actuality. The first chapter traces these developments in Aristotle, including the distinction between energeia and kinesis and the arguments for the priority of actuality in the Metaphysics. ;One of Aristotle's most influential applications of the concept of energeia was the theory of the Prime Mover. The Prime Mover is a being whose "essence is energeia"; here energeia is both activity and actuality, for the Prime Mover is nothing other than the self-subsistent activity of thought. Chapter 2 argues that a proper understanding of energeia illuminates much that has traditionally been found puzzling about the Prime Mover. ;Later thinkers were fascinated by the Prime Mover and often attempted to incorporate a similar conception of God into their own systems. In doing so they further exploited the possibilities inherent in the fusion of the notions of activity and actuality. Chapter 3 discusses such developments in Theophrastus, Philo of Alexandria, Numenius, Alcinous, and Alexander of Aphrodisias. It also examines the evolution of the word among non-philosophical authors, where energeia was beginning to take on a sense similar to the modern term 'energy.' ;The final two chapters discuss energeia among the Neoplatonists. Chapter 4 is devoted to the theory of two acts in Plotinus, one of the most interesting and innovative adaptations of energeia in its "fused" sense. Chapter 5 turns to the followers of Plotinus in the West: Porphyry, Marius Victorinus, and the author of the Anonymous Commentary on the Parmenides. It examines their reflections on the notion of a God who is both supremely active and supremely real, ending with a look at how, through the mediation of Boethius, these reflections prepared the way for the Thomistic conception of the act of being