Having thus cleared the ground, our young idealist proceeds in his next and greatest work, _Of the Principles of Human Knowledge_, to attack the problem from another side. The world of objects revealed through sensation and reflection is clearly no illusion, no creation of our own. We find it there, changing, when it changes, without or even very much against our will. {74} What, then, is its origin and nature? Locke's view, which is the common view, tells us that it consists of material bodies, some animated and some not. And matter, the supposed substance of body, is made known to us by impressions on our organs of sense. But when we try to think of matter apart from these sensible qualities and the relations between them it vanishes into an empty abstraction. Now, according to Berkeley there are no abstract ideas--_i.e._, no thoughts unassociated with some mental image besides a mere word; and Matter or inanimate substance would be such an idea, therefore it does not exist. There is nothing but mind and its contents--what we call states of consciousness, what Locke and Berkeley called ideas. Whence, then, come the objects of our consciousness, and whither do they go when we cease to perceive them? At this point the new metaphysical system intervenes. Berkeley says that all things subsist in the consciousness of God, and by their subsistence his existence is proved. The direct apprehension of a reality that is not ourselves only becomes possible through what would be called in modern language a subjective participation in the divine consciousness, more feebly reflected, as would seem, in the memories, imaginations, and reasonings of our finite minds.