Sextus Empiricus Pyrrhoniae Hypotyposes 3.30.270

[270] Such, then, are the objections put forward regarding learning and teaching in general. And the same difficulties may also be alleged in the case of the so-called art of living. Thus, for instance, we have shown above ¹ that the matter taught, namely prudence, is non-existent; and both the teacher and the learner are non-existent. For either the prudent man will teach the prudent the art of living, or the imprudent the imprudent, or the imprudent the prudent, or the prudent the imprudent; but none of these teaches any other; therefore the so-called art of living is not taught.