Metaphysics (Book I.e. 6), a passage containing an account of the ideas, which hitherto scholars have found impos- sible to reconcile with the statements of Plato himself. The preparations for the new departure are discovered in the Parmenides and in the Theaetetus ; and it is said to be expressed under a different form by the irepay and the a-neipov of the Philcbus (vol. x. 275 foil.). The irfpas of the Philebus is the principle which gives form and measure to the aireipov; and in the ' Later Theory' is held to be the 7700-0;^ or jxiTpiov which converts the Infinite or Indefinite into ideas. They are neither irepaivovTa nor a-aupa, but belong to the p.iKTov yivo's which partakes of both.
With great respect for the learning and ability of Dr. Jackson, I find myself unable to agree in this newly fashioned doctrine of the Ideas, which he ascribes to Plato. I have not the space to go into the question fully; but I will briefly state some objections which are, I think, fatal to it.
(1). First, the foundation of his argument is laid in the Metaphysics of Aristotle. But we cannot argue, either from the Metaphysics, or from any other of the philo- sophical treatises of Aristotle, to the dialogues of Plato until we have ascertained the relation in which his so- called works stand to the philosopher himself. There is of course no doubt of the great influence exercised upon Greece and .upon the world by Aristotle and his philo- sophy. But on the other hand almost every one who is capable of understanding the subject acknowledges that his writings have not come down to us in an authentic form like most of the dialogues of Plato. How much of them is to be ascribed to Aristotle's own hand, how much is due to his successors in the Peripatetic School, is a question which has never been determined, and probably
