But St. Thomas, as we shall see further on, does not confound ideal with universals, nor does he hold genera and species to be simply the abstraction or generalization of the qualities of individuals or particulars. Genera and species are real, or there could be no generation. But the genus or species does not exist apart from its individualization, or as a separate entity. There are no individuals without the race, and no race without individuals. Thus the whole race was individualized in Adam, so that in his sin all men sinned. {148} But as genera and species, the only real universals, do not exist apart from their particulars, and are distinctly possessed or apprehended only as disengaged from their particulars, which is done only by a mental operation, St. Thomas might say they exist _in mente cum fundamento in re_, without asserting them to be real only as properties or qualities of particulars. Plato is commonly held to be the father of the ideal philosophy or ideal realism. We know very little of the philosophy that prevailed before him, and cannot say how much of the Platonic philosophy is original with him, or how much of it he took from his predecessors, but he is its originator as far as our knowledge extends. It is from him that we have the word _idea_, and his whole philosophy is said to be in his doctrine of ideas; but what his doctrine of ideas really was is a question. He seems when treating the question, What is it necessary to know in order to have real science? to understand by idea _causa essentialis_, or the thing itself, or what in anything is real, stable, and permanent, in distinction from the sensible, the phenomenal, the variable, and the transitory. The real existence of things is their ideas, and ideas are in the Logos or divine mind. These ideas God impresses on an eternally existing matter, as the seal upon wax, and so impressed they constitute particulars. Aristotle accuses Plato of placing the ideas _extra Deum_, and making them objects of the divine contemplation, but the accusation is not easily sustained; and we think all that Plato does is to represent the ideas as _extra Deum_ only as the idea or design of a picture or a temple in the mind of the artist is distinguishable from the artist himself. But in God all ideas must be eternal, and therefore really his essence, as is maintained by St. Thomas. If this is really Plato's doctrine, it is dualism inasmuch as it asserts the eternity of matter, and pantheism inasmuch as the ideas, the reality of things, are identical with the divine mind, and therefore with God himself. On this doctrine, what is that soul the immortality of which Plato so strenuously maintains? Is it the divine idea, or the copy of the idea on matter?