[209] For example, Sextus Empiricus, in spite of his constant formula, οὐχ ὁρίζω, maintains the necessity of having definable conceptions, τῶν ἐννοουμένων ἡμῖν πραγμάτων τὰς οὐσίας ἐπινοεῖν ὀφείλομεν, and he argues that it is impossible for a man to have an ἔννοια of God because He has no admitted οὐσία, _Pyrrh. Hypot._ 3. 2, 3. [210] Origen, _c. Cels._ 3. 44: see also the references given in Keim, _Celsus’ wahres Wort_, pp. 11, 40. [211] Origen, _c. Cels._ 1. 9. [212] _Apol._ i. 20. [213] _De testim. animæ_, 1. [214] _Apol._ 46. [215] _Apol._ 2. 13. [216] _Octav._ 34. [217] _Apol._ 47. [218] _Strom._ 2. 1. [219] Origen, _c. Cels._ 3. 16. [220] Origen, _c. Cels._ 5. 65; 6. 1, 7, 15, 19: see also the references in Keim, p. 77. [221] _Ibid._ 7. 58. So Minucius Felix, in Keim, p. 157. [222] The above slight sketch of some of the leading tendencies which have been loosely grouped together under the name of Gnosticism has been left unelaborated, because a fuller account, with the distinctions which must necessarily be noted, would lead us too far from the main track of the Lecture: some of the tendencies will re-appear in detail in subsequent Lectures, and students will no doubt refer to the brilliant exposition of Gnosticism in Harnack, _Dogmengeschichte_, i. pp. 186-226, ed. 2. [223] _Strom._ 1. 1: almost the whole of the first book is valuable as a vindication of the place of culture in Christianity. [224] _Adv. Prax._ 3. [225] Quoted by Euseb. _H. E._ 5. 28. 13. [226] _Orat. ad Græc._ 2. [227] _Apol._ 46. [228] _Refut. omn. hæres._ 5. 18. [229] _H. E._ 5. 13. [230] The evidence for the above statements has not yet been fully gathered together, and is too long to be given even in outline here: the statements are in full harmony with the view of the chief modern writer on the subject, Friedländer, _Darstellungen aus der Sittengeschichte Roms_, see especially Bd. iii. p. 676, 5te aufl. [231] This is sufficiently shown by the fact, which is in other respects to be regretted, that in most accounts of Stoicism the earlier and later elements are viewed as constituting a homogeneous whole. [232] “How am I to eat?” said a man to Epictetus: “So as to please God,” was the reply (_Diss._ 1. 13). The idea is further developed in Porphyry, who says: “God wants nothing” (281. 15): the God who is ἐπὶ πᾶσιν is ἄϋλος; hence all ἔνυλον is to Him ἀκάθαρτον, and should therefore not be offered to Him, not even the spoken word (163. 15). [233] M. Aurelius owed to Rusticus the idea that life required διόρθωσις and θεραπεία (i. 7 and ii. 13). [234] τὸ ὑλακτεῖν, Philostr. 587. [235] The title of _Diss._ 3. 22, in which the ideal philosopher is described, is περὶ Κυνισμοῦ. [236] H. Schiller, _Geschichte der römischen Kaiserzeit_, Bd. i. 452.