Our beliefs are subject to multiple sources of error: a traveler's perception of an oasis in the desert may turn out to be a mirage; the key witness in a trial criminal may turn out to be lying; or a fluke in the data may mislead a research team into believing a false hypothesis; or a miscalculating math student may end up with the wrong answer. Philosophers often characterize knowledge as belief that is safe from error--but is knowledge possible? This course uses the philosophical arguments and thought experiments to assess the question of how much we can hope to know. Class Notes: Introductory Seminar. Preference to first-year students; sophomores admitted if space available. Advance sign-up process and deadlines at http://introsems.stanford.edu.