We now enter on the last period of purely objective philosophy, an age of mediating and reconciling, but still profoundly original speculation. Its principal representatives, with whom alone we have to deal, are Empedocles, the Atomists, Leucippus and Democritus, and Anaxagoras. There is considerable doubt and difficulty respecting the order in which they should be placed. Anaxagoras was unquestionably the oldest and Democritus the youngest of the four, the difference between their ages being forty years. It is also nearly certain that the Atomists came after Empedocles. But if we take a celebrated expression of Aristotle’s[21] literally (as there is no reason why it should not be taken), Anaxagoras, although born before Empedocles, published his views at a later period. Was he also anticipated by Leucippus? We cannot tell with certainty, but it seems likely from a comparison of their doctrines that he was; and in all cases the man who naturalised philosophy in Athens, and who by his theory of a creative reason furnishes a transition to the age of subjective speculation, will be most conveniently placed at the close of the pre-Socratic period. A splendid tribute has been paid to the fame of Empedocles by Lucretius, the greatest didactic poet of all time, and by a great didactic poet of our own time, Mr. Matthew Arnold. But the still more rapturous panegyric pronounced by the Roman enthusiast on Epicurus makes his testimony a little suspicious, and the lofty chant of our own contemporary must be taken rather as an expression of his own youthful opinions respecting man’s place in Nature, than as a faithful exposition of the Sicilian thinker’s creed. Many another name from the history of philosophy might with better reason have been prefixed to that confession of resigned and scornful scepticism entitled _Empedocles on Etna_. The real doctrines of an essentially religious teacher would hardly have been so cordially endorsed by Mr. Swinburne. But perhaps no other character could have excited the deep sympathy felt by one poetic genius for another, when with both of them thought is habitually steeped in emotion. Empedocles was the last Greek of any note who threw his philosophy into a metrical form. Neither Xenophanes nor Parmenides had done this with so much success. No less a critic than Aristotle extols the Homeric splendour of his verses, and Lucretius, in this respect an authority, speaks of them as almost divine. But, judging from the fragments still extant, their speculative content exhibits a distinct decline from the height reached by his immediate predecessors. Empedocles betrays a distrust in man’s power of discovering truth, almost, although not quite, unknown to them. Too much certainty would be impious. He calls on the ‘much-wooed white-armed virgin muse’ to— ‘Guide from the seat of Reverence thy bright car, And bring to us the creatures of a day, What without sin we may aspire to know.’[22]