To illustrate, let us consider one kind of metaphysics that has an influence in our day. In the Western world many people among the intelligentsia think that the world consists in matter and motion and energy. According to this view, more complex things, like rocks and trees, animals and people, are built up from complex arrangements and interactions of matter. But the ultimate nature of the world is material. This view is called materialism. It is one kind of metaphysical position, that is, one