posite principle, with its logical developments, must be accepted as
an established truth_.

[Footnote 576: Confutation is the greatest and chiefest of
purification.--"Sophist," Sec. 34.]

[Footnote 577: Article "Plato," Encyclopaedia Britannica.]

By the application of this method, Plato had not only exposed the
insufficiency and self-contradiction of all results obtained by a mere
_a posteriori_ generalization of the simple facts of experience, but he
demonstrated, as a consequence, that we are in possession of some
elements of knowledge which have not been derived from sensation; that
there are, in all minds, certain notions, principles, or ideas, which
have been furnished by a higher faculty than sense; and that these
notions, principles, or ideas, transcend the limits of experience, and
reveal the knowledge of _real being_--to ontos on--_Being in se_.

To determine what these principles or ideas are, Plato now addresses
himself to the _analysis of thought_. "It is the glory of Plato to have
borne the light of analysis into the most obscure and inmost region; he
searched out what, in this totality which forms consciousness, is the
province of reason; what comes from it, and not from the imagination and
the senses--from within, and not from without."[578] Now to analyze is
to decompose, that is, to divide, and to define, in order to see better
that which really is. The chief logical instruments of the dialectic
method are, therefore, _Division_ and _Definition_. "The being able to
_divide_ according to genera, and not to consider the same species as
different, nor a different as the same,"[579] and "to see under one
aspect, and bring together under one general idea, many things scattered
in various places, that, by _defining_ each, a person may make it clear
what the subject is," is, according to Plato, "dialectical."[580]

[Footnote 578: Cousin's "Lectures on the History of Philosophy," vol. i.
p. 328.]

[Footnote 579: "Sophist," Sec. 83.]

[Footnote 580: "Phaedrus," Secs. 109, 111.]

We have already seen that, in his first efforts at applying reflection
to the concrete phenomena of consciousness, Plato had recognized two
distinct classes of cognitions, marked by characteristics essentially
opposite;--one of "_sensible_" objects having a definite outline, limit,
and figure, and capable of being imaged and represented to the mind in a
determinate form--the other of "_intelligible_" objects, which can not
be