§§72--78. Summary. You accuse me of appealing to ancient names like a revolutionist, yet Anaxagoras, Democritus, and Metrodorus, philosophers of the highest position, protest against the truth of sense knowledge, and deny the possibility of knowledge altogether (72, 73). Empedocles, Xenophanes, and Parmenides all declaim against sense knowledge. You said that Socrates and Plato must not be classed with these. Why? Socrates said he knew nothing but his own ignorance, while Plato pursued the same theme in all his works (74). Now do you see that I do not merely name, but take for my models famous men? Even Chrysippus stated many difficulties concerning the senses and general experience. You say he solved them, even if he did, which I do not believe, he admitted that it was not easy to escape being ensnared by them (75). The Cyrenaics too held that they knew nothing about things external to themselves. The sincerity of Arcesilas may be seen thus (76). Zeno held strongly that the wise man ought to keep clear from _opinion_. Arcesilas agreed but this without _knowledge_ was impossible. _Knowledge_ consists of _perceptions_. Arcesilas therefore demanded a definition of _perception_. This definition Arcesilas combated. This is the controversy which has lasted to our time. Do away with _opinion_ and _perception_, and the εποχη of Arcesilas follows at once (77, 78). §72. _De antiquis philosophis_: on account of the somewhat awkward constr. Lamb. read _antiquos philosophos_. _Popularis_: cf. 13. _Res non bonas_: MSS. om. _non_, which Or. added with two very early editions. Faber ingeniously supposed the true reading to be _novas_, which would be written _nobas_, and then pass into _bonas_. _Nivem nigram_: this deliverance of Anaxagoras is very often referred to by Sextus. In _P.H._ I. 33 he quotes it as an instance of the refutation of φαινομενα by means of νοουμενα, "Αναξαγορας τωι λευκην ειναι την χιονα, ανετιθει ‛οτι χιων εστιν ‛υδορ πεπηγος το δε ‛υδορ εστι μελαν και ‛η χιων αρα μελαινα." There is an obscure joke on this in _Ad Qu. Fratrem_ II. 13, 1 _risi nivem atram ... teque hilari animo esse et prompto ad iocandum valde me iuvat_. _Sophistes_: here treated as the demagogue of philosophy. _Ostentationis_: = επιδειξεος.