Appendix I. Phaedo, Antisthenes, and in the next generation Aristotle, arc 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 con- sider 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 : (i) 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 one but Plato. And