In Greece the traditional polytheism was challenged, as we have seen, at once on the side both of morals and metaphysics. To Xenophanes, indeed, the unity of God is even more essential than His morality, and the attack on anthropomorphism is as much an attack upon the number of the gods of Hesiod as upon the immoral character attributed to them. In the unity, however, which Xenophanes contends for, the religious idea of God is so attenuated, that we hardly know whether the One God is a person, or an abstraction. Indeed, it is hard to see how a champion of Eleaticism could consistently have held the personality of God, as we understand it, without falling under his own charge of anthropomorphism. In Plato the same difficulty appears, only complicated or relieved by the fact that while from the moral side he talks like a theist, from the metaphysical his teaching is pantheistic. Is the 'Idea of Good' personal? Is it a God we can love and worship, or only a God we can talk about? Is the vision of Er a concession to popular views, or the vehicle of moral and religious truth? The question is hardly more easy to decide with regard to Aristotle. The religious atmosphere, which lingers on in Plato, has disappeared. What of the religious belief? Did Aristotle in any intelligible sense hold the personality of God? Great names are ranged on both sides of the mediaeval controversy. Who shall decide? But whether or no anything of religion survived in philosophy, it was not strong enough to withstand the attack of the moral and the speculative reason, still less to claim these as its own. It is not on the side of religion, but of speculation, that we are debtors to the Greeks.