Galen was one of the most prolific intellectuals of western antiquity, his works extending to 21 volumes of roughly 1000 pages each in the standard Greek edition (with a few additional works surviving only in Arabic, Syriac, Hebrew or Latin translations)—a total of more than 4 million words. While most of his scientific and medical writings survive, many of his specialist works of philosophy do not. He is an extremely adversarial author, a vigorous participant in the highly rhetorical and learned competitive intellectual culture of second-century-CE Rome (the so-called “Second Sophistic”); and he is extremely prone to digression. He often expresses his own views through the twin media of polemic against his opponents and textual interpretation and commentary on his intellectual heroes, especially Plato and Hippocrates. And, in spite of his profound knowledge of the Greek philosophical tradition and “classic” philosophical texts and his use of philosophical terminology and modes of argument, he does not define himself as a philosopher, often expressing hostility towards “school” practitioners of philosophy.