Philo of Larissa, Greek philosopher of the first half of the ist century B.C. During the Mithradatic wars he left Athens and took up his residence in Rome. He was a pupil of Clitomachus, whom he succeeded as head of the Third or New Academy. According to Sextus Empiricus, he was the founder of the Fourth Academy, but other writers refuse to admit the separate existence of more than three academies (see ACADEMY, GREEK). In Rome he lectured on rhetoric and philosophy, and collected around him many eminent pupils, amongst whom Cicero was the most famous and the most enthusiastic. None of his works is extant; our knowledge of his views is derived from Numenius, Sextus Empiricus and Cicero. In general, his philosophy was a reaction against the sceptic or agnostic position of the Middle and New Academy in favor of the dogmatism of Plato.

See Grysar, Die Akademiker Philo und Antiochus (1849); Hermann, De Philone Larissaeo (Gottingen, 1851 and 1855).