In a recent article written by Mr. G. E. L. Owen to prove that contrary to the general current opinion the composition of the Timaeus must have antedated that of the Parmenides and its dialectical successors, it is contended that when the Timaeus was written the analysis of negation given in the Sophist could not yet have been worked out. ‘For’, Mr. Owen writes, ‘the tenet on which the whole new account of negation is based, namely that τὸ μὴ ὄν ἔστιν ὄντως μὴ ὄν (Soph. 254D1), is contradicted unreservedly by Timaeus' assertion that it is illegitimate to say τὸ μὴ ὄν ἔστι μὴ ὄν (38B2–3); and thereby the Timaeus at once ranks itself with the Republic and Euthydemus.' After brushing aside Cornford's attempt to reconcile this passage of the Timaeus with the Sophist, Mr. Owen concludes his treatment of it with the words: ‘So the Timaeus does not tally with even a fragment of the argument in the Sophist. That argument is successful against exactly the Eleatic error which, for lack of the later challenge to Father Parmenides, persists in the Timaeus.’
An examination of the other arguments put forward by Mr. Owen in support of his thesis concerning the relative chronology of the Timaeus I reserve for another place. Here I propose to consider only the meaning of this one passage and whether it really does imply that the Timaeus must have been written before Plato had conceived the doctrine enunciated in the Sophist. It is a question not now raised for the first time. More than half a century ago Otto Apelt asserted that this passage of the Timaeus is enough to prove that work earlier than the Sophists. His assertion did not go unchallenged; and Apelt himself appears to have lost his original confidence in it, for in his later writings on the relative chronology of the two dialogues he did not again refer to it.