th 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 [Greek: epoche] of Arcesilas follows at once
(77, 78).

Sec.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 [Greek: phainomena] by means of
[Greek: nooumena], "[Greek: Anaxagoras toi leuken einai ten chiona,
anetithei hoti chion estin hydor pepegos to de hydor esti melan kai he
chion ara melaina]." 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_: = [Greek: epideixeos].

Sec.73. _Democrito_: Cic., as Madv. remarks on _D.F._ I. 20, always
exaggerates the merits of Democr. in order to depreciate the Epicureans,
cf. _T.D._ I. 22, _De Div._ I. 5, II. 139, _N.D._ I. 120, _De Or._ I. 42.
_Quintae classis_: a metaphor from the Roman military o