Plato's was essentially a dualistic theory. To him, the divine ideas, the universals, the general qualities, the genera, were the only real beings, that, like the deities, had an absolute, independent existence. God himself was the supreme idea. The man, the animal, the beautiful, the good, the brave, and so on, represented realities, the archetypes of life of which the individuals, the earthly forms of those general qualities, as they appeared in daily life, were mere shadows and faint replicas.... Aristotle connected the two spheres by seeing the spiritual soul and the intrinsic idea as the formative principle of the body, and, at the same time, as an "entelechy," an innate, ideal goal of the individual that effects evolution. The individuals, then, participate in the essential reality of ideas. This participation becomes effective when man comprehends the ideas and their connections, when he gathers and abstracts the ideas from their multifold, individual manifestation, in short, when he thinks logically. This procedure implied the legitimacy of empirical observation, and of inductive conclusion from observed facts to abstract generalities.
