In modern times, and under Christian influences, these several systems are almost necessarily identified with inquiries concerning the existence and nature of God. The influence of Christianity has been indirectly felt, even in speculations prosecuted in apparent independence of it; and the admission of an absolute first principle of all things distinct from God, or the acknowledgment of a God separate from or derived from the first principle of all things, is an absurdity which, since the prevalence of Christianity, has become almost impossible, even to antichristian systems of thought. In earlier times, indeed, this union of philosophy with theology was by no means so imperative. A philosophy like that of Greece, which inherited its speculations from a poetical theogony, would see no difficulty in attributing to the god or gods of its religious belief a secondary and derived existence, dependent on some higher and more original principle, and in separating that principle itself from all immediate connection with religion. It was possible to assume, with the Ionian, a material substance, or, with the Eleatic, an indifferent abstraction, as the first principle of things, without holding that principle to be God, or, as the only alternative, denying the existence of a God; and thus, as Aristotle[A] has observed, theologians endeavoured to evade the consequences of their abstract principles, by attributing to the chief good a later and derived existence, as the poets supposed the supreme God to be of younger birth than night and chaos and sea and sky. But to a Christian philosophy, or to a philosophy in any way influenced by Christianity, this method of evasion is no longer possible. If all conditioned existence is dependent on some one first and unconditioned principle, either that principle must be identified with God, or our philosophical speculations must fall into open and avowed atheism. [A] _Metaph._, xiv. 4.