The Timaeus of Plato

INTROD UCTIOtf. 1 5
obviously our business is to investigate his mode of operation at
both stages
: we must see how he endeavoured in the first instance
to escape from the philosophical scepticism which seemed to be
the inevitable result
of previous speculation, what were the deficiencies
he found in the earlier form of his theory, and how he proposed
to remedy
its faults. We must see too how far his conception
of the nature of the problem may have altered in the interval
between the earlier and the later phase of the ideal theory.
To this end it will be necessary to examine Plato's metaphysical
teaching as propounded in a group of dialogues,
whereof the most important metaphysically are the Republic and
Phaedo with which are in accordance the Phaednts, Symposium,
Meno, and apparently the Cratylus and next the amended
form of their teaching, as it appears in four great dialogues of the
later period, Parmenides, Sophist, Philebus, Timaeus ; especially
of course the last. The Sokratic dialogues may be dismissed
as not bearing upon our question.
1 6. Plato had thoroughly assimilated the physical teaching Plato
of Herakleitos. He held no less strongly than the Ionian philosopher
the utter instability and fluidity of material nature. We tean stand
are not perhaps at liberty to allege the very emphatic language Pomt>
of the Theaetetus as evidence that this was his view in the earlier
phase of his philosophy, with which we are at present dealing :
but there is abundant proof within the limits of the Republic
and Phaedo; see Republic 4796, Phaedo 788. He therefore,
like Protagoras, was bound to draw his inference from the Herakleitean
principle. The inference drawn by Protagoras was that
speculation is idle, knowledge impossible. The inference drawn
by Plato was that, since matter cannot be known, there must
be some essence transcending matter, which alone is the object
of knowledge. And furthermore this immaterial essence must
be the cause and sole reality of material phenomena. Thus it
was Plato's acceptance of the Herakleitean TrdvTa. pei, together
with his refusal to infer from it the impossibility of knowledge,
that led him to idealism.
At this point the hint from Sokrates is worked in. What Thecontrimanner
of immaterial essence is it which we are to seek as the gokrates
object of knowledge ? Plato cordially adopted the Sokratic and the
principle that universals alone can be known. But the Sokratic ^ as
universal, being no substantial existence but merely a con- presented
ception in our own mind, will not meet Plato's demand for a