Except for Descartes, then, we should not be conscious of the gulf that yawns between the individual mind and the universe in front of it. He presented the opposition as between mind and matter. The essence of the former is thought; of the latter, extension. The conceptions are disparate and opposed. No interaction is possible. His disciples, more consistent than their master, called in a _deus ex machina_,--the miraculous intervention of God,--in order to account for the appearance of reciprocal action between the universe of matter and the thinking individual. Thus they in substance admitted the relation between them to be scientifically inexplicable, and had recourse to the supernatural. The individual does not act upon the universe to produce, destroy, or alter the arrangement of anything. But upon the _occasion_ of his volition God produces a corresponding material change. The world does not act upon the soul of the individual to produce thoughts or sensations. God, upon _occasion_ of the external affection, brings them into being. With such thoroughness Descartes performed his task of separation. Yet the introduction of the _deus ex machina_ only complicated the problem; it introduced a third factor where two were already too many. What is the relation of God to Mind and to Matter? Is it simply a third somewhat, equally distinct from both, or does it contain both within itself? Spinoza attempted to solve the problem in the latter sense. He conceived God to be the one substance of the universe, possessing the two known attributes of thought and matter. These attributes are one in God; indeed, he is their unity. This is the sole legitimate outcome of the Cartesian problem stated as Descartes would have it stated. It overcomes the absoluteness of the dualism by discovering a common and fundamental unity, and at the same time takes the subject out of the realm of the miraculous. For the solution works both ways. It affects the nature of God, as well as of extension and thought. It presents him to us, not as a supernatural being, but as the unity of thought and extension. In knowing these as they are, we know God as he is. Spinoza, in other words, uses the conception of God in a different way from the Cartesians. The latter had treated him as the God of theology,--a being supernatural; Spinoza uses the conception as a scientific one, and speaks of _Deus sive Natura_.