Yet the very fact that Galen’s major treatise on psycho-physiology, PHP, is formally presented as a reconciliation of Hippocrates’ and Plato’s views is telling—as indeed is the huge volume of exegetical work on Hippocrates, and on Aristotelian logic. In practice, arguments from authority have considerable value for Galen, at least as a persuasive tool, in spite of his explicit denials of that authority status; and there are undoubtedly cultural and historical reasons for his devotion to Plato and Hippocrates in particular (see von Staden 1997; Vegetti 1999; Gill et al. 2009). However, his claim not to be a slavish sectarian is borne out; and no one—not Aristotle, not Plato, not even Hippocrates—is exempt from criticism in particular contexts.