Plotinus' epistemology and his reading of the Theaetetus Sara Magrin Department of Philosophy McGill University, Montreal July 2009 A thesis submitted to McGill University in partial fulfilment of the requirements of the degree of Doctor of Philosophy Copyright Sara Magrin 2009 Abstract: Plotinus' epistemology and his reading of the Theaetetus The thesis offers a reconstruction of Plotinus’ reading of the Theaetetus, and it presents an account of his epistemology that rests on that reading. It aims to show that Plotinus reads the Theaetetus as containing two anti-sceptical arguments. The first argument is an answer to radical scepticism, namely, to the thesis that nothing is apprehensible and judgement must be suspended on all matters. The second argument is an answer to a more moderate form of scepticism, which does not endorse a universal suspension of judgement, but maintains nonetheless that scientific knowledge is unattainable. The first chapter opens with a reconstruction of Plotinus’ reading of Theaet., 151e-184a, where Socrates examines the thesis that knowledge is sensation in light of Protagoras’ epistemology. In this chapter it is argued that Plotinus makes a polemical use of the discussion of Protagoras’ epistemology. Plotinus takes Plato to show that Protagoras’ views imply radical scepticism; and he attack the Stoics’ epistemological and ontological commitments by arguing that they imply Protagoras’ views, and thus lead to radical scepticism, too. The second chapter examines Plotinus’ interpretation of the ontology of the Timaeus. In Theaet., 151e-184a Plato shows that Protagoras’ epistemology leads to radical scepticism by arguing that it implies an allegedly Heracleitean conception of the sensible world. Plotinus maintains that in the Timaeus Plato offers an alternative to Protagoras’ and Heracleitus’ ontology. This alternative conception of the sensible world provides some of the premises on which Plotinus builds his interpretation of Theaet., Part I, 184b- 187a. The third chapter reconstructs Plotinus’ reading of Theaet., 184b-187a. In this chapter it is argued that Plotinus takes the discussion of sensation at Theaet., 184b-186b 11 to remove the threat to knowledge that is presented by radical scepticism, while he reads Theaet., 186b 11-187a as presenting an argument against the more moderate forms of scepticism described above. The third chapter also offers an overview of Plotinus’ reading of the Theaetetus in its entirety and it suggests that this dialogue for Plotinus represents a Platonic exercise in Socratic dialectic that aims to prepare the student for the dialectic of the Sophist. Résumé : L’épistémologie de Plotin et son interpretation du Thééthète Cette thèse reconstruit la lecture plotinienne du Thééthète, et elle présente une analyse de l’épistémologie de Plotin qui s’appui sur cette lecture. Le but de ce travail et de montrer que Plotin identifie dans le Thééthète deux arguments contre le scepticisme. Le premier argument est une réponse à une forme de scepticisme radicale, c’est-à-dire à la thèse selon laquelle rien n’est connaissable et le jugement doit être suspendu sur toute chose. Le second argument est une réponse à une forme plus modérée de scepticisme, qui n’appui pas une suspension du jugement universelle, mais maintient quand même qu’on ne peut pas atteindre la connaissance. Le premier chapitre reconstruit la lecture plotinienne de Theaet., 151e-184a, où Socrate analyse la thèse que la connaissance est sensation à la lumière de l’épistémologie de Protagoras. Dans ce chapitre on observe que Plotin emploie à des fins polémiques la discussion de l’épistémologie de Protagoras. Plotin pense que pour Platon l’épistémologie de Protagoras implique un scepticisme radical, et il attaque l’épistémologie et l’ontologie des stoïciens en essayant de démontrer qu’elles impliquent la position de Protagoras, si bien qu’elles aussi amènent à une forme de scepticisme radical. Le deuxième chapitre analyse la lecture plotinienne de l’ontologie du Timée. Dans Theaet., 151e-184a, Platon montre que l’épistémologie de Protagoras amène au scepticisme radical en soutenant qu’elle implique une conception du monde sensible de type héraclitéen. Plotin soutient que dans le Timée Platon présente une alternative à l’ontologie de Protagoras et d’Héraclite. Cette nouvelle conception du monde sensible fournit des prémisses sur lesquelles Plotin construit son interprétation de Theaet., 184b-187a. Le troisième chapitre reconstruit la lecture plotinienne de Theaet., 184b-187a. Dans ce chapitre on suggère que Plotin voit dans Theaet., 184b-186b un argument qui vise à éliminer la menace d’un scepticisme radical, et qu’il voit dans Theaet., 186b 11-187a un argument qui vise à réfuter une forme de scepticisme plus modérée, telle que celle décrite en haute. Le troisième chapitre présente aussi une vision d’ensemble de la lecture que Plotin fait du dialogue et il suggère que ce dialogue pour Plotin représente un exercice de dialectique socratique qui prépare le lecteur à la lecture du Sophiste. Per Rosa, Brian e Caterina ACKNOWLEDGEMENTS My first debt of gratitude goes to my supervisor Prof. Stephen Menn, for the care and kindness with which he has directed my work in the past years. Every page of this thesis has benefitted from his suggestions, and from his unfailing attempts to steer me away from error. I want to thank my co-supervisor Prof. Richard Bodéüs for his comments and his generous encouragement. Special thanks go to Cristina D’Ancona, Eyólfur Emilsson, Paul Kalligas, Claude Panaccio, Steven Strange, and Brian van den Broek for their invaluable help with different parts of the dissertation. Marwan Rashed and Philippe Hoffmann helped me greatly during a yearlong staying in Paris where I had access to the the wonderful library of the École Normale Supérieure. May they be warmly thanked here. I am grateful to the faculty of the department of philosophy of McGill University for having accepted me in their Ph.D. program, and as a recipient of the Tomlinson doctoral fellowship I want to thank Doctor Richard Tomlinson and the faculty of graduate studies for their financial support over the years. CONTENTS Introduction 1 Chapter 1: Plotinus on Theaetetus Part I (151e-184a) 18 1.1. Readings of Theaet., 151e-184a 18 1.2. Plotinus and the Stoics on the real being of bodies 24 1.3. The Stoics’ ontology and their theory of categories 26 1.4. III.6.[26]: Plotinus’ criticism of the Stoics’ first two 34 categories 1.5. Conflicting appearances vs. cataleptic representations 48 1.6. VI.6.[34]: Plotinus’ criticism of the Stoics’ third category 59 1.7. The Stoics and the Theaetetus 66 1.8. The Stoics and the refutation of Protagoras 82 1.9. The antecedents of Plotinus’ anti-Stoic strategy 86 Chapter 2: From Protagoras to Plato: the ontology of the Timaeus 91 2.1. Are sensible qualities illusions? 91 2.2. Abandoning atomism 102 2.3. The intelligible structure of bodies: II.6.[17] 115 2.4. Lo/goi as natures 133 2.5. Plotinus’ account of necessity in the sensible world 144 2.6. Lo/goi and “forms in us” 148 2.7. Sensible qualities are indestructible: the Stoics and Aristotle 152 2.8. The inexhaustibility of generation: Aristotle 160 2.9. The inexhaustibility of generation: Plotinus 162 2.10. The identity of bodies through time 167 2.11. The issue of a)ntitupi/a 175 2.12. Matter 180 Chapter 3: Plotinus on Theaetetus Part I (184b-187a) 188 3.1. Plotinus and the reductio ad Protagoram 188 3.2. Readings of Theaetetus Part I: 184b-187a 192 3.3. The Wooden Horse psychology and Plotinus’ conception of 197 the soul 3.4. Sensation is a judgement of the soul 207 3.5. Sensation is a judgement of the soul: Aristotle 222 3.6. The Cyrenaics and Protagoras 229 3.7. Theaet., 184b-d: the Wooden Horse psychology and the 232 removal of akatalēpsia 3.8. Theaet., 184d-186c 5: sensation as a judgement of the soul 241 3.9. Theaet., 186c 6-187a 8: sensory representations and beliefs 250 3.10. A summary of Plotinus’ reading of Theaet., 184b-187a 256 3.11. The direct realist reading of sensory judgement 259 3.12. Criteria of truth 270 3.13. Plotinus’ reading of Theaetetus Part II 275 3.14. Plotinus and the anonymous commentator on the Theaetetus 284 Conclusion 286 Bibliography 290 Introduction In book III of the Contra Academicos, Augustine presents a short account of the history of the Academy.1 Plato, he says, built a complete system of philosophy, and he maintained that there are two worlds: the intelligible world, in which truth and knowledge can be found, and the sensible world—an image of the true world—, where there is only truth-like opinion. But, not long after Plato’s death, the Academy underwent a considerable change. Zeno, who was to be the founder of Stoicism, began to attend the school, and he started spreading inside and outside the Academy some un-Platonic views. He maintained that only the sensible world existed, and that the soul and God were bodies. Alarmed by these views, Plato’s successors began to preserve the doctrine of the master as a “mystery” to be guarded from those men whose “impure” minds were not prepared to receive it. The first to adopt this policy was Arcesilaus, a fellow student of Zeno, who became the head of the so- called New or Second Academy. Arcesilaus thought that there was no point in trying to teach Plato to people whose minds were cluttered by mistaken beliefs, and he made it his priority to free from error those who had been wrongly taught. Afraid that Plato’s teachings could have been distorted, he buried them, as “a golden treasure” to be uncovered by future generations, and he assumed a sceptical attitude, professing two things: that nothing could be apprehended, and that judgement had to be suspended on all matters.