6
Chrysippus (c. 280-207 B.C.) was a Stoic philosopher who became head of the Stoa after Cleanthes. His works, which are lost, were most influential and were generally accepted as the authoritative interpretation of orthodox Stoic philosophy.—Ed.
7
Cleanthes, in Diogenes Laertius, quoted also by Seneca, Epistle 107.
8
Euripides, Fragments.
9
Plato, Crito, Chap. XVII.
10
Plato, Apology, Chap. XVIII.
11
Chapter XV of the third book of the Discourses, which, with the exception of some very trifling differences, is the same as chapter XXIX of the Enchiridion.—Ed.