As a philosopher, Favorinus belonged to the sceptical school; his most important work in this connexion appears to have been Hvppwvetot rpoiroc (the Pyrrhonean Tropes) in ten books, in which he endeavours to show that the methods of Pyrrho were useful to those who intended to practise in the law courts.
To him are ascribed the five tropes (pente tropoi) which, according to Sextus Empiricus, summarize the attitude of the later ancient sceptics.
A comparison of these tropes with the ten tropes enumerated in the article Aenesidemus shows that scepticism has made an advance into the more abtruse questions of metaphysics.
The first and the third include all the ideas expressed in the ten tropes, and the other three systematize the more profound difficulties which new thinkers had developed.
It abounds not only in antitheses, but also in questions and exclamations, tropes and metaphors, and other mannerisms of the silver age.