FURTHER DEVELOPMENT OF THE THEORY OF IDEAS.
IN the Republic Plato puts the coping-stone upon his ideal theory by asserting not merely the existence of a number of independent ideas, but the systematic unity of all ideas under one supreme principle, a principle at once of all reality and of all thought. But, with this conception of the ultimate unity of all things with each other and with the mind, Plato's philosophy seems to enter upon a second stage of development, which carries him still farther away from the abstract idealism commonly attributed to him. For hitherto he has looked upon the idea mainly as a unifying principle--a principle which we need not, indeed, take as a mere abstraction, but which is so far abstract as it leaves out many of the aspects of the manifold and changing phenomena, and has no differences or determinations but such as flow from its own nature. There is, however, a great danger of misunderstanding when