Physical theories now began to spring up which modified the metaphysical theories; and these produced results which while not so logical, were less distant from the facts of life. The Eleatics had so conceived Being as to deny the existence of changing phenomena perceived in the world of nature. On the other hand, Heracleitus had so emphasized the universality of change that there was little reality left in the particular changes. The later Heracleitans were Heracleitus gone mad. “We not only cannot step into the same river twice, but we cannot do it once.” All the preceding philosophers had been monists. The time had therefore come for thinkers to abandon monism if thought were to have any usefulness. Monism, whether in the form of Heracleitus’ doctrine of universal change or of Parmenides’ doctrine of universal permanence, had merely set aside the problem about the Many. Of course, a more satisfactory solution of this problem could come only when human life had become riper and had more experiences upon which to draw. It was natural for the Greek philosopher to look now to pluralism for his solution, when he turned away from monism. _At the outset pluralism tried to reconcile the two extremes to which the Milesian motifs had gone._ Its later development in the doctrine of Protagoras was as extreme as that of the monists. =The New Conception of Change of the Pluralists.= Facing the fact that change has to be explained and cannot be denied, change is conceived by the pluralists to be not a transformation but a transposition. It is an alteration in position of the parts of a mass. Birth, growth, death, are only such changes of transposition. Empedocles, to whom the origin of the doctrine is attributed, says, “There is no coming into Being of aught that perishes, nor any end for it in baneful death, but only a mingling and a separation of what has been mingled. Just as when painters are elaborating temple offerings,――they, when they have taken the pigments of many colors in their hands, mix them in a harmony,――so let not the error prevail in thy mind that there is any other source of all the perishable creatures that appear in countless numbers.” All origination, then, is a new combination, and every destruction only a separation of the original parts. The Pluralists thus make Heracleitus’ conception useful in the explanation of nature.