8. One point for preliminary consideration is this: By ideas, two things may be meant. Ideas may either be a name for thought or knowledge in its simplest, lowest, easiest, or most elementary form; in that form in which knowledge is possessed by all human beings, even the most uninstructed; or ideas may be a name for that higher and more complex kind of knowledge called science, which is the possession of comparatively few. In which of these acceptations, then, does Plato employ the term? Do his ideas mean knowledge of the simplest character, knowledge which no man can open his eyes without receiving? or do they mean knowledge of a loftier order, and which it requires some exertion to attain to?
9. The true answer, I believe, is, that by ideas Plato intends to designate both kinds of knowledge, the lower and the higher. But as he employs the word more frequently, and with greater emphasis, in reference to our higher than to our lower knowledge, one is apt to think that his theory of ideas is rather a theory of science in its loftiest pretensions, than a theory of thought and knowledge simply, and in their humblest and commonest manifestations. The consequence has been, that his expositors have usually expounded the ideas as more peculiarly the property of the scientific mind, and as acquisitions which it required a large amount of philosophic culture to get possession of.
