While much of medieval and Renaissance grammar, logic, and meta physics was based on interpretations of classical texts, it would be a mistake to assume that the texts of Plato and Aristotle that were read in the thir teenth, fourteenth and fifteenth centuries were equivalent to those we recognize as genuine today.1 A number of spurious texts were included among the canonical works of Aristotle, and discrepancies in translations and manuscript editions of texts often resulted in variations among editions of the same work. Furthermore, as I will discuss in the next section, the ‘Aristotelian’ philosophy of scholastic authors such as Thomas Aquinas should not be equated with the philosophy of Aristotle himself, since medieval authors’ interpretations drew on a wide variety of sources, and in many cases went to great lengths to reconcile Greek philosophy with Christian doctrine, often at the expense of fidelity to the original texts. This is particularly an issue when confronting sixteenth and seventeenth century critiques of ‘Aristotelian’ philosophy, which are often directed more at scholastic interpretations than at the actual teachings of Aristotle. It is still true, however, that most of the central issues in episte

mology over the past two millennia received their first systematic treatment by either Plato or Aristotle, and that later authors both realist and nominalist consciously built on these foundations. The positions produced in classical antiquity that we are concerned with can be grouped roughly as follows: (1) the actual teachings of Plato and Aristotle; (2) independent mathematical works by technical authors such as Apollonius, Euclid, Archimedes, and others; (3) commentaries on either Plato or Aristotle, such as Proclus’ highly influential Platonic reading of Euclid; and (4) reactions against Plato and/or Aristotle, including those of the Epicureans, Stoics, and the Academic and Pyrrhonian skeptical schools. This group ing reflects those works or philosophical movements that were most directly influential during the Renaissance and Scientific Revolution, and my sketch here is mostly for the purpose of contextualizing the later portions of this study. It is not intended as a comprehensive survey of classical epistemology.2