THREE:No sooner did the two imperial systems lose their ascendency than the germs which they had temporarily overshadowed sprang up into vigorous vitality, and for more than4 five centuries dominated the whole course not only of Greek but of European thought. Of these by far the most important was the naturalistic idea, the belief that physical science might be substituted for religious superstitions and local conventions as an impregnable basis of conduct. In a former chapter1 we endeavoured to show that, while there are traces of this idea in the philosophy of Heracleitus, and while its roots stretch far back into the literature and popular faith of Greece, it was formulated for the first time by the two great Sophists, Prodicus and Hippias, who, in the momentous division between Nature and Law, placed themselvesHippias more particularlyon the side of Nature. Two causes led to the temporary discredit of their teaching. One was the perversion by which natural right became the watchword of those who, like Platos Callicles, held that nothing should stand between the strong man and the gratification of his desire for pleasure or for power. The other was the keen criticism of the Humanists, the friends of social convention, who held with Protagoras that Nature was unknowable, or with Gorgias that she did not exist, or with Socrates that her laws were the secret of the gods. It was in particular the overwhelming personal influence of Socrates which triumphed. He drew away from the Sophists their strongest disciple, Antisthenes, and convinced him that philosophy was valuable only in so far as it became a life-renovating power, and that, viewed in this light, it had no relation to anything outside ourselves. But just as Socrates had discarded the physical speculations of former teachers, so also did Antisthenes discard the dialectic which Socrates had substituted for them, even to the extent of denying that definition was possible.2 Yet he seems to have kept a firm hold on the two great ideas that were the net result of all previous philosophy, the idea of a cosmos, the common citizenship of which made all men5 potentially equal,3 and the idea of reason as the essential prerogative of man.4As remarked in the case of other machines treated of, there is no use of describing the mechanism of trip-hammers; it is presumed that every engineer apprentice has seen trip-hammers, or can do so; and the plan here is to deal especially with what he cannot see, and would not be likely to learn by casual observation.
