the Platonic writing was common to several of
his contemporaries. Aeschines, Euclid, Phaedo, Antisthenes, and in the
next generation Aristotle, are all said to have composed dialogues; and
mistakes of names are very likely to have occurred. Greek literature in
the third century before Christ was almost as voluminous as our own, and
without the safeguards of regular publication, or printing, or binding,
or even of distinct titles. An unknown writing was naturally attributed
to a known writer whose works bore the same character; and the name once
appended easily obtained authority. A tendency may also be observed to
blend the works and opinions of the master with those of his scholars.
To a later Platonist, the difference between Plato and his imitators was
not so perceptible as to ourselves. The Memorabilia of Xenophon and the
Dialogues of Plato are but a part of a considerable Socratic literature
which has passed away. And we must consider how we should regard the
question of the genuineness of a particular writing, if this lost
literature had been preserved to us.

These considerations lead us to adopt the following criteria of
genuineness: (1) That is most certainly Plato's which Aristotle
attributes to him by name, which (2) is of considerable length, of (3)
great excellence, and also (4) in harmony with the general spirit of
the Platonic writings. But the testimony of Aristotle cannot always
be distinguished from that of a later age (see above); and has various
degrees of importance. Those writings which he cites without mentioning
Plato, under their own names, e.g. the Hippias, the Funeral Oration, the
Phaedo, etc., have an inferior degree of evidence in their favour. They
may have been supposed by him to be the writings of another, although in
the case of really great works, e.g. the Phaedo, this is not credible;
those again which are quoted but not named, are still more defective
in their external credentials. There may be also a possibility that
Aristotle was mistaken, or may have confused the master and his scholars
in the case of a short writing; but this is inconceivable about a more
important work, e.g. the Laws, especially when we remember that he was
living at Athens, and a frequenter of the groves of the Academy, during
the last twenty years of Plato's life. Nor must we forget that in all
his numerous citations from the Platonic writings he never attributes
any passage found in the extant dialogues to any