the contempt of even the most accomplished of our modern 'physiologists of mind.' "—(Butler's 'Lectures on Philosophy,' vol. ii. pp. 117-18-19.)
16. Before entering on the exposition of Plato's dialectic or theory of ideas, I thought it right to call your attention to certain preliminary considerations. These were the settlement of the question, Are the Platonic ideas the necessary constituents of all knowledge, or only of scientific knowledge? My conclusion is that they are, according to Plato, the necessary constituents of all knowledge, although it must be confessed that he has left this point somewhat ambiguous, and has thereby misled his expositors, who frequently regard the ideas as belonging more properly to scientific than to ordinary cognition. The true interpretation is, that while all minds have ideas, the instructed mind both has and knows that it has them. I then mentioned the sciences which, in the opinion of Plato, were the best preparation for dialectic; these were arithmetic and the mathematical sciences, particularly geometry. These, when rightly cultivated, lead the mind to look at truth, not in the particular, but in the universal, and thus furnish a proper training for the higher study of ideas. As a further introduction to dialectic, and in order to familiarise you with the main object of Plato's philosophy, which is to turn the mind from the comparative unrealities of sense to the realities of reason, which ideas are, I read to you his cele-
