Phôs: Plato’s Doctrine of Light

This thesis deals with Plato’s conception and use of light (phôs) across a selection of dialogues. In the extensive secondary literature on Plato, when the topic of light is touched on, the main, if not the only, work considered is the Republic. However, Plato appeals to light frequently and in different ways across his works. There are therefore numerous scenarios, outside the Republic, in which references to light are made in a philosophically relevant manner. In this thesis, I identify and analyse such references, in addition to the ones of the Republic, in a systematic and comparative way. Thus I argue that they provide several less known insights into what Plato thinks about light as a physical entity of both optical and cosmological interest, as well as into how he uses the respective image as a metaphor at the service of philosophical purposes. The thesis that I defend is based on the following three tenets: first, the necessity of a full-length study of the topic focused on an abundant selection of dialogues, hence neither confined to the Republic, nor limited to the mere listing of other works potentially pertinent, but devoted to the cross-examination of the respective relevant passages; second, an original interpretation of Plato’s conception and use of light; third, the conclusion according to which the references to light taking place across the dialogues are not circumstantial and unrelated to one another, but parts and steps of a consistent philosophical plan, which I address in terms of a doctrine. This plan is aimed at finding, in an object of the physical world and thus in the respective image, a most suitable symbol for the link connecting to one another the salient points of Plato’s ontology, cosmology, epistemology, and practical philosophy. Plato finds such an object in light.