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Proclus on Aristotle on Plato. A Case Study on Motion



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Marinescu, Rares 


My PhD thesis focuses on Proclus (412–485 AD) and his engagement with Aristotle’s theory of motion with a specific focus on Aristotle’s criticism of Plato. There are two main goals. (i) I refute the widespread view that Proclus – in line with other Neoplatonists – adheres to the idea of an essential harmony between Plato and Aristotle. (ii) I illuminate Proclus’ views on motion, which is a central concept in his thought, by examining his Aristotelian background. The thesis is divided in four chapters. The first chapter deals with Proclus’ little studied treatise Elements of Physics where he sums up in an axiomatic manner Aristotle’s theory of motion from Physics VI, VIII and De Caelo I. I demonstrate that Proclus’ project is embedded in an exegetical tradition and show how he omits certain parts of Aristotle’s works which might conflict with his Neoplatonist views. Additionally, I provide evidence for the view that Aristotle’s Posterior Analytics proved to be influential for the axiomatic structure of Proclus’ treatise. The second chapter concerns the origin of motion in the universe. While Plato assumes a self-moving soul as origin, Aristotle posits an unmoved intellect. Proclus brings these two views together by regarding the unmoved intellect as ultimate source of motion and the self-moving soul as an intermediate entity. I demonstrate that his harmonisation effort goes beyond previous Platonist attempts due to the philosophical reasoning he provides. I also defend Proclus’ assumption of both unmoved intellect and self-moving soul as sources of motion against concerns brought up in scholarship. In the third chapter, I focus on the concept of self-motion which is tied to the definition of soul in Plato. Aristotle famously criticises this view in De Anima I.3, showing that the soul is unmoved. I offer the first lengthy discussion of Proclus’ repudiation of Aristotle’s criticism which differs from other Neoplatonist responses. Most importantly, I demonstrate how Proclus develops his own views on self-motion by using Platonic and Aristotelian insights. The fourth chapter examines the problem of the causality of the unmoved intellect. This issue is central in scholarship on Aristotle and goes back to late antiquity. I argue that here Proclus’ non-harmonist stance towards Aristotle emerges most strongly: not only did Aristotle fail to make the intellect an efficient cause of the cosmos’ being but his metaphysics generally is deficient since he did not recognise the Platonic One as highest principle. I contrast Proclus’ view with the position of Ammonius and Simplicius who see a complete agreement between Plato and Aristotle.





Hatzimichali, Myrto
Warren, James


Proclus, Aristotle, Plato, Neoplatonism, Metaphysics, Physics, Late Antiquity


Doctor of Philosophy (PhD)

Awarding Institution

University of Cambridge
Cusanuswerk Faculty of Classics, Cambridge