ause of all the rest.
They seem, however, to have lost their first aspect of universals under
which individuals are contained, and to have been converted into forms
of another kind, which are inconsistently regarded from the one side as
images or ideals of justice, temperance, holiness and the like; from the
other as hypotheses, or mathematical truths or principles.

In the Timaeus, which in the series of Plato's works immediately follows
the Republic, though probably written some time afterwards, no mention
occurs of the doctrine of ideas. Geometrical forms and arithmetical
ratios furnish the laws according to which the world is created. But
though the conception of the ideas as genera or species is forgotten or
laid aside, the distinction of the visible and intellectual is as
firmly maintained as ever. The IDEA of good likewise disappears and is
superseded by the conception of a personal God, who works according to
a final cause or principle of goodness which he himself is. No doubt is
expressed by Plato, either in the Timaeus or in any other dialogue, of
the truths which he conceives to be the first and highest. It is not the
existence of God or the idea of good which he approaches in a tentative
or hesitating manner, but the investigations of physiology. These he
regards, not seriously, as a part of philosophy, but as an innocent
recreation (Tim.).

Passing on to the Parmenides, we find in that dialogue not an exposition
or defence of the doctrine of ideas, but an assault upon them, which is
put into the mouth of the veteran Parmenides, and might be ascribed to
Aristotle himself, or to one of his disciples. The doctrine which is
assailed takes two or three forms, but fails in any of them to escape
the dialectical difficulties which are urged against it. It is admitted
that there are ideas of all things, but the manner in which individuals
partake of them, whether of the whole or of the part, and in which
they become like them, or how ideas can be either within or without
the sphere of human knowledge, or how the human and divine can have any
relation to each other, is held to be incapable of explanation. And
yet, if there are no universal ideas, what becomes of philosophy?
(Parmenides.) In the Sophist the theory of ideas is spoken of as a
doctrine held not by Plato, but by another sect of philosophers, called
'the Friends of Ideas,' probably the Megarians, who were very distinct
from him, if not opposed to him (Sop