A re-examination of the anonymous Commentary on the Theaetetus, henceforth abbreviated K, is overdue. It may yet prove to be the most important document we possess for plotting the course of pre-Plotinian Platonism, and is by far the largest surviving portion of a pre-Plotinian commentary on a complete work of Plato. It offers us insights into the issues of the first century B.C. which are unparalleled in other extant Middle Platonist works, either because of the subject of the work and (...) its consequent tendency to bring to mind the epistemological debates between Philo of Larissa, Antiochus of Ascalon, and Aenesidemus, or because the author, whom we may call A, is writing at a time comparatively close to those debates. (shrink)