In this connection, too, the dualism of Plato's system becomes evident. If everything is grounded in the one ultimate reality, the Ideas, then the entire universe must be clasped together in a system, all parts of which flow out of the Ideas. If there exists in the universe anything which stands aloof from this system, remains isolated, and cannot be reduced to a manifestation of the Ideas, then the philosophy has failed to explain the world, and we have before us a confessed dualism. Now not only has Plato to drag in God for the explanation of things, he has also to drag in matter. God takes matter and forms it into copies of the Ideas. But what is this matter, and where does it spring from? Clearly, if the sole reality is the Ideas, matter, like all else, must be grounded in the Ideas. But this is not the case in Plato's system. Matter appears as a principle quite independent of the Ideas. As its being is self-derived and original, it must be itself a substance. But this is just what Plato denies, calling it absolute {239} not-being. Yet since it has not its source in the Ideas or in anything outside itself, we must say that though Plato calls it absolute not-being, it is in fact an absolute being. The Ideas and matter stand face to face in Plato's system neither derived from the other, equally ultimate co-ordinate, absolute realities. This is sheer dualism. The source of this dualism is to be found in the absolute separation which Plato makes between sense and reason. He places the world of sense on one side, the world of reason on the other, as things radically different and opposed. Hence it is impossible for him ever to bridge the gulf that he has himself created between them. We may expect the dualism of a philosophy which builds upon such premises to break out at numerous points in the system. And so indeed it does. It exhibits itself as the dualism of Ideas and matter, of the sense-world and the thought-world, of body and soul. Not, of course, that it is not quite right to recognize the distinction between sense and reason. Any genuine philosophy must recognize that. And no doubt too it is right to place truth and reality on the side of reason rather than sense. But although sense and reason are distinct, they must also be identical. They must be divergent streams flowing from one source. And this means that a philosophy which considers the absolute reality to be reason must exhibit sense as a lower form of reason. Because Plato fails to see the identity of sense and reason, as well as their difference, his philosophy becomes a continual fruitless effort to overreach the dualism thus generated.