Let us now consider some parts of his philosophy. He criticized Plato’s doctrine that ideas have an existence apart from things, and not unjustly charged that Plato had taken the universals, which we arrive at by abstraction, and had elevated these general concepts into eternal and immortal elements, claiming for them that they were anterior to the things of sense and alone had real existence. In his own philosophy he took a position fundamentally opposed to that of Plato, for he insisted that “ideas,” “forms” and the phenomenal world could not exist apart, for if they did, then we should be obliged to postulate a third world beyond them; that is to say, that if the idea of man, for example, had a substantial existence apart from individual men, then there would have to be an idea antecedent to both the idea of man and the individual men, the model of both, and this idea would be a “third man.” He further pointed out that men know the ideas only in the concrete objects, never apart from those objects of which they are the ideas, that the essence can never be separated from that of which it is the essence, since then both thing and essence would cease to exist. So he charged Plato with using meaningless poetic metaphors when he said that ideas, forms, existed apart from things. Reality to Aristotle was always in the individual object, itself an indissoluble union of matter and form. Of course he recognized that the human mind could abstract these two elements each from the other and could think of the matter and the form as separate, but he would not allow that these abstractions had substantial reality in the sense that they could ever exist by themselves.[214]