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 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.; Polit.; Cratyl), although he has not
always avoided the confusion of them in his own writings (e.g. Rep.).
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).

Neither must we forget that the Republic is but the third part of a
still larger design which was to have included an ideal history of
Athens, as well as a political and physical philosophy. The fragment of
the Critias has given birth to a world-famous fiction, second only in
importance to the tale of Troy and the legend of Arthur; and is said as
a fact to have inspired some of the early navigators of the sixteenth
century. This mythical tale, of which the subject was a history of the
wars of the Athenians against the Island of Atlantis, is supposed to be
founded upon an unfinished poem of Solon, to which it would have stood
in the same relation as the writings of the logographers to the poems of
Homer. It would have told of a struggle for Liberty (cp. Tim.), intended
to represent the conflict of Persia and Hellas. We may judge from the
noble commencement of the Timaeus, from the fragment of the Critias
itself, and from the third book of the Laws, in what manner Plato would
have treated this high argument. We can only guess why the great design
was abandoned; perhaps because Plato became sensible of some incongruity
in a fictitious history, or because he had lost his interest in it, or
because advancing years forbade the completion of it; and we may please
ourselves with the fancy that had this imaginary narrative ever been
finished, we should have found Plato himself sympathisi