As in the Cratylus and Parmenides, we are uncertain whether Plato is
expressing his own opinions, or appropriating and perhaps improving the
philosophical speculations of others. In all three dialogues he is
exerting his dramatic and imitative power; in the Cratylus mingling a
satirical and humorous purpose with true principles of language; in the
Parmenides overthrowing Megarianism by a sort of ultra-Megarianism, which
discovers contradictions in the one as great as those which have been
previously shown to exist in the ideas. There is a similar uncertainty
about the Timaeus; in the first part he scales the heights of
transcendentalism, in the latter part he treats in a bald and superficial
manner of the functions and diseases of the human frame. He uses the
thoughts and almost the words of Parmenides when he discourses of being and
of essence, adopting from old religion into philosophy the conception of
God, and from the Megarians the IDEA of good. He agrees with Empedocles
and the Atomists in attributing the greater differences of kinds to the
figures of the elements and their movements into and out of one another.
With Heracleitus, he acknowledges the perpetual flux; like Anaxagoras,
he asserts the predominance of mind, although admitting an element of
necessity which reason is incapable of subduing; like the Pythagoreans he
supposes the mystery of the world to be contained in number. Many, if not
all the elements of the Pre-Socratic philosophy are included in the
Timaeus. It is a composite or eclectic work of imagination, in which
Plato, without naming them, gathers up into a kind of system the various
elements of philosophy which preceded him.

If we allow for the difference of subject, and for some growth in Plato's
own mind, the discrepancy between the Timaeus and the other dialogues will
not appear to be great. It is probable that the relation of the ideas to
God or of God to the world was differently conceived by him at different
times of his life. In all his later dialogues we observe a tendency in him