According to Aristotle, the Heracleitean flux was inconsistent with the highest law of thought, and made all predication impossible. It has been shown that the master himself recognised a fixed recurring order of change which could be affirmed if nothing else could. But the principle of change, once admitted, seemed to act like a corrosive solvent, too powerful for any vessel to contain. Disciples were soon found who pushed it to extreme consequences with the effect of abolishing all certainty whatever. In Plato’s time it was impossible to argue with a Heracleitean; he could never be tied down to a definite statement. Every proposition became false as soon as it was uttered, or rather before it was out of the speaker’s mouth. At last, a distinguished teacher of the school declined to commit himself by using words, and disputed exclusively in dumb show. A dangerous speculative crisis had set in. At either extremity of the Hellenic world the path of scientific inquiry was barred; on the one hand by a theory eliminating non-existence from thought, and on the other hand by a theory identifying it with existence. The luminous beam of reflection had been polarised into two divergent rays, each light where the other was dark and dark where the other was light, each denying what the other asserted and asserting what the other denied. For a century physical speculation had taught that the universe was formed by the modification of a single eternal substance, whatever that substance might be. By the end of that period, all becoming was absorbed into being at Elea, and all being into becoming at Ephesus. Each view contained a portion of the truth, and one which perhaps would never have been clearly perceived if it had not been brought into exclusive prominence. But further progress was impossible until the two half-truths had been recombined. We may compare Parmenides and Heracleitus to two lofty and precipitous peaks on either side of an Alpine pass. Each commands a wide prospect, interrupted only on the side of its opposite neighbour. And the fertilising stream of European thought originates with neither of them singly, but has its source midway between.
IV.
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’s21 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
We also miss in him their single-minded devotion to philosophy and their rigorous unity of doctrine. The Acragantine sage was a party leader (in which capacity, to his great credit, he victoriously upheld the popular cause), a rhetorician, an engineer, a physician, and a thaumaturgist. The well-known legend relating to his death may be taken as a not undeserved satire on the colossal self-conceit of the man who claimed divine honours during his lifetime. Half-mystic and half-rationalist, he made no attempt to reconcile the two inconsistent sides of his intellectual character. It may be compared to one of those grotesque combinations in which, according to his morphology, the heads and bodies of widely different animals were united during the beginnings of life before they had learned to fall into their proper places. He believed in metempsychosis, and professed to remember the somewhat miscellaneous series of forms through which his own personality had already run. He had been a boy, a girl, a bush, a bird, and a fish. Nevertheless, as we shall presently see, his theory of Nature altogether excluded such a notion as the soul’s separate existence. We have now to consider what that theory actually was. It will be remembered that Parmenides had affirmed the perpetuity and eternal self-identity of being, but that he had deprived this profound divination of all practical value by interpreting it in a sense which excluded diversity and change. Empedocles also declares creation and destruction to be impossible, but explains that the appearances so denominated arise from the union and separation of four everlasting substances—earth, air, fire, and water. This is the famous doctrine of the four elements, which, adopted by Plato and Aristotle, was long regarded as the last word of chemistry, and still survives in popular phraseology. Its author may have been guided by an unconscious reflection on the character of his own philosophical method, for was not he, too, constructing a new system out of the elements supplied by his predecessors? They had successively fixed on water, air, and fire as the primordial form of existence; he added a fourth, earth, and effected a sort of reconciliation by placing them all on an equal footing. Curiously enough, the earlier monistic system had a relative justification which his crude eclecticism lacked. All matter may exist either in a solid, a liquid, or a gaseous form; and all solid matter has reached its present condition after passing through the two other degrees of consistency. That the three modifications should be found coexisting in our own experience is a mere accident of the present régime, and to enumerate them is to substitute a description for an explanation, the usual fault of eclectic systems. Empedocles, however, besides his happy improvement on Parmenides, made a real contribution to thought when, as Aristotle puts it, he sought for a moving as well as for a material cause; in other words, when he asked not only of what elements the world is composed, but also by