been already discussed with some fulness under these separate headings. [Sidenote: The elements.] =190.= The position of the four ‘elements’ (στοιχεῖα, _elementa_) is similar; these are in the Stoic philosophy subdivisions of the two principles just discussed. For fire and air are of the nature of cause and movement; water and earth of receptivity and passivity[108]. Body is therefore made up of the four elements mixed[109], or perhaps rather of the elementary qualities of heat and cold, dry and wet, which they represent[110]. The doctrine of primary or elemental qualities had been taught before, first by Anaximenes, then by Hippocrates the physician, and by Aristotle[111]; the list of the four elements is traced back to Empedocles. For Aristotle’s ‘fifth element’ Zeno found no use[112]. [Sidenote: Conclusion.] =191.= Such are the fundamental conceptions or postulates with which the Stoics approach the problems of physics. It is not necessary for our purpose to compare their merit with those of Aristotle, or to set a value on the debt that Zeno and his successors owed to the founder of the Peripatetic school. Still less do we suggest that the Stoics have perfectly analyzed the contents of the universe, or have even produced an orderly and rounded scheme. But at least it seems clear that their work shews intellectual power, and that speculation is not necessarily less profound because it is pursued with a practical aim[113]. The founders of the Stoic philosophy had a wide reach; they took all knowledge to be their province; and they worked persistently towards the harmonization of all its parts. FOOTNOTES [1] Diog. L. vii 41. [2] Arnim ii 42 and 44. [3] Diog. L. vii 40. [4] Perhaps necessarily: on the definition of monism, see above, § 35, note 22. [5] See above, §§ 149, 153. [6] ‘[Zeno] nullo modo arbitrabatur quicquam effici posse ab ea [natura], quae expers esset corporis ... nec vero aut quod efficeret aliquid aut quod efficeretur, posse esse non corpus’ Cic. _Ac._ i 11, 39; ‘cui tanta vis est, ut inpellat et cogat et retineat et iubeat, corpus est’ Sen. _Ep._ 106, 9. [7] See above, § 67. [8] § 43. [9] See above, § 157, note 84. [10] ταὐτὸν σῶμα καὶ οὐσίαν ὁριζόμενοι Clem. Alex. _Strom._ ii p. 436 (Arnim ii 359); διδόασι δὲ καὶ σῶμα αὐτῇ [τῇ ὕλῃ] Plot. _Enn._ ii 4, 1 (Arnim ii 320). οὐσία in this sense is also called πρώτη ὕλη, see § 182, note 52. [11] τὸν θεὸν ... σῶμα νοερὸν ... ποιοῦντες Plut. _comm. not._ 48, 2. [12] ‘vides autem tanto spiritum esse faciliorem omni alia materia, quanto tenuior est’ Sen. _Ep._ 50, 6. [13] ‘et hoc [animus] corpus est’ _ib._ 106, 4. [14] οἱ Στωϊκοὶ πάντα τὰ αἴτια σωματικά· πνεύματα γάρ Aët. _plac._ i 11, 5; ‘placet nostris quod bonum est, corpus esse’ Sen. _Ep._ 117, 2; ‘quaeris, bonum an corpus sit. bonum facit, prodest enim. quod facit, corpus est’ _ib._ 106, 4.