 As a philosopher, Favorinus considered himself to be an Academic Skeptic; his most important work in this connection appears to have been the "Pyrrhonean Tropes" in ten books, in which he endeavours to show that the Pyrrhonist Ten Modes of Aenesidemus were useful to those who intended to practise in the law courts.Galen devoted to a polemic against Favorinus in "De optima doctrina", opposing Favorinus’ thesis that the best instruction consists in the argument in which one speaks, in each particular question, in favour of opposite sides.Galen's treatise says that Favorinus wrote a work "On the Academic Disposition" also called "Plutarch" and a work against Epictetus named "Against Epictetus" staging one of Plutarch’s slaves, Onesimus, arguing with Epictetus.