TWO:The year 155 B.C. was signalised by an important event, if not in the history of ideas, at least in the history of their diffusion. This was the despatch of an embassy from the Athenian people to the Roman Senate, consisting of three philosophers, the heads of their respective schools��Carneades the Academician, Critolaus the Peripatetic, and Diogenes the Stoic. Philosophic teaching, once proscribed at Athens, had, at the time of which we are speaking, become her chief distinction, and the most honourable profession pursued within her precincts. It was, then, as natural that an important mission should be confided to the most eminent representatives of the calling in question as that high ecclesiastics should be similarly employed by Rome in later ages, or that German university towns should send professors to represent their interests in the imperial Diet. But the same fate that befalls an established religion had befallen an established philosophy. An attempt to impose restrictions on the liberty of teaching had, indeed, been successfully resisted, and the experiment was never repeated.212 Nevertheless, the teachers themselves lost as much in true dignity as they gained in affluence and popular estimation. In all probability, the threat of death would not have induced Socrates to undertake the task which was, apparently, accepted without121 compulsion and as an honourable duty by his successors. The Athenians had made an unprovoked raid on the town of Oropus; the affair had been referred to arbitration; and the aggressors had been sentenced to pay a fine of 500 talents. It was to obtain a remission of this sentence that the three Scholarchs were sent on an embassy to the Roman Senate.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 themselves��Hippias more particularly��on 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 Plato��s 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.4