main
doctrines of Plato, as they may be gathered from a general view of
them, we are at once met by difficulties many and serious. In the case
of a genius such as Plato's, at once ironical, dramatic, and
allegorical, we cannot be absolutely certain that in any given passage
Plato is expressing, at all events adequately and completely, his own
personal views, even at the particular stage of his own mental
development then represented. And when we add to this that in a long
life of unceasing intellectual development, Plato inevitably grew out
of much that once satisfied him, and attained not infrequently to new
points of view even of doctrines or conceptions which remained
essentially unchanged, a Platonic dogma in the strict sense must
clearly not be expected. One may, however, attempt in rough outline to
summarise the main {163} _tendencies_ of his thought, without
professing to represent its settled and authenticated results.

[251]

We may begin by an important summary of Plato's philosophy given by
Aristotle (_Met_. A. 6): "In immediate succession to the Pythagorean
and Eleatic philosophies came the work of Plato. In many respects his
views coincided with these; in some respects, however, he is
independent of the Italians. For in early youth he became a student of
Cratylus and of the school of Heraclitus, and accepted from them the
view that the objects of sense are in eternal flux, and that of these,
therefore, there can be no absolute knowledge. Then came Socrates, who
busied himself only with questions of morals, and not at all with the
world of physics. But in his ethical inquiries his search was ever for
universals, and he was the first to set his mind to the discovery of
definitions. Plato following him in this, came to the conclusion that
these universals could not belong to the things of sense, which were
ever changing, but to some other kind of existences. Thus he came to
conceive of universals as forms or _ideas_ of real existences, by
reference to which, and in consequence of analogies to which, the
things of sense in every case received their names, and became
thinkable objects."

From this it followed to Plato that in so far as the senses took an
illusive appearance of themselves giving {164} the knowledge which
really was supplied by reason as the organ of ideas, in the same degree
the body which is the instrument of sense can only be a source of
illusion and a hindrance to knowledge. The