THE Republic of Plato is the longest of his works with the exception of
the Laws, and is certainly the greatest of them. There are nearer
approaches to modern metaphysics in the Philebus and in the Sophist; the
Politicus or Statesman is more ideal; the form and institutions of the
State are more clearly drawn out in the Laws; as works of art, the
Symposium and the Protagoras are of higher excellence. But no other
Dialogue of Plato has the same largeness of view and the same perfection
of style; no other shows an equal knowledge of the world, or contains more
of those thoughts which are new as well as old, and not of one age only
but of all. Nowhere in Plato is there a deeper irony or a greater wealth
of humour or imagery, or more dramatic power. Nor in any other of his
writings is the attempt made to interweave life and speculation, or to
connect politics with philosophy. The Republic is the centre around which
the other Dialogues may be grouped; here philosophy reaches the highest
point (cp. especially in Books V, VI, VII) to which ancient thinkers ever
attained. Plato among the Greeks, like Bacon among the moderns, was the
first who conceived a method of knowledge, although neither of them always
distinguished the bare outline or form from the substance of truth; and
both of them had to be content with an abstraction of science which was
not yet realized. He was the greatest metaphysical genius whom the world
has seen; and in him, more than in any other ancient thinker, the germs of
future knowledge are contained. The sciences of logic and psychology,
which have supplied so many instruments of thought to after-ages, are
based upon the analyses of Socrates and Plato. The principles of
definition, the law of contradiction, the fallacy of arguing in a circle,
the distinction between the essence and accidents of a thing or notion,
between means and ends, between causes and conditions; also the division
of the mind into the rational, concupiscent, and irascible elements, or of
pleasures and desires into necessary and unnecessary--these {ii} and other
great forms of thought are all of them to be found in the Republic, and
were probably first invented by Plato. The greatest of all logical truths,
and the one of which writers on philosophy are most apt to lose sight, the
difference between words and things, has been most strenuously insisted on
by him (cp. Rep. 454 A; Polit. 261 E; Cratyl. 435, 436 ff.), although he
has not always avoided the confusion of them in his own writings (e.g.
Rep. 463 E). But he does not bind up truth in logical formulae,--logic is
still veiled in metaphysics; and the science which he imagines to
'contemplate all truth and all existence' is very unlike the doctrine of
the syllogism which Aristotle claims to have discovered (Soph. Elenchi 33.
18).