The argument is an old one into whose merits this is not the place to enter. But one thing is certain, that the sceptical spirit which was invading religion, was invading also politics and ethics; and that towards the close of the fifth century before Christ, Greece and in particular Athens was overrun by philosophers, who not only did not scruple to question the foundations of social and moral obligation, but in some cases explicitly taught that there were no foundations at all; that all law was a convention based on no objective truth; and that the only valid right was the natural right of the strong to rule. It was into this chaos of sceptical opinion that Plato was born; and it was the desire to meet and subdue it that was the motive of his philosophy. Like Aristophanes, he traced the root of the evil to the decay of religious belief; and though no one, as we have seen, was more trenchant than he in his criticism of the popular faith, no one, on the other hand, was more convinced of the necessity of some form of religion as a basis for any stable polity. The doctrine of the physicists, he asserts, that the world is the result of "nature and chance" has immediate and disastrous effects on the whole structure of social beliefs. The conclusion inevitably follows that human laws and institutions, like everything else, are accidental products; that they have no objective validity, no binding force on the will; and that the only right that has any intelligible meaning is the right which is identical with might. [Footnote: See e.g. Plato's "Laws". X. 887.] Against these conclusions the whole soul of Plato rose in revolt. To reconstruct religion, he was driven back upon metaphysics; and elaborated at last the system which from his day to our own has not ceased to perplex and fascinate the world, and whose rare and radiant combination of gifts, speculative, artistic, and religious, marks the highest reach of the genius of the Greeks, and perhaps of mankind. To attempt an analysis of that system would lead us far from our present task. All that concerns us here, is its religious significance; and of that, all we can note is that Plato, the deepest thinker of the Greeks, was also among the farthest removed from the popular faith. The principle from which he derives the World is the absolute Good, or God, of whose ideas the phenomena of sense are imperfect copies. To the divine intelligence man by virtue of his reason is akin. But the reason in him has fallen into bondage of the flesh; and it is the task of his life on earth, or rather of a series of lives (for Plato believed in successive re-incarnations), to deliver this diviner element of his soul, and set it free to re-unite with God.