affinity to spurious writings can be detected, or which seem to have
originated in a name or statement really occurring in some classical
author, are also of doubtful credit; while there is no instance of any
ancient writing proved to be a forgery, which combines excellence with
length. A really great and original writer would have no object in
fathering his works on Plato; and to the forger or imitator, the 'literary
hack' of Alexandria and Athens, the Gods did not grant originality or
genius. Further, in attempting to balance the evidence for and against a
Platonic dialogue, we must not forget that the form of 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