of the same arguments does not involve the inference that he knew the work.
And, if the Parmenides is spurious, like Ueberweg, we are led on further
than we originally intended, to pass a similar condemnation on the
Theaetetus and Sophist, and therefore on the Politicus (compare Theaet.,
Soph.). But the objection is in reality fanciful, and rests on the
assumption that the doctrine of the Ideas was held by Plato throughout his
life in the same form. For the truth is, that the Platonic Ideas were in
constant process of growth and transmutation; sometimes veiled in poetry
and mythology, then again emerging as fixed Ideas, in some passages
regarded as absolute and eternal, and in others as relative to the human
mind, existing in and derived from external objects as well as transcending
them. The anamnesis of the Ideas is chiefly insisted upon in the mythical
portions of the dialogues, and really occupies a very small space in the
entire works of Plato. Their transcendental existence is not asserted, and
is therefore implicitly denied in the Philebus; different forms are
ascribed to them in the Republic, and they are mentioned in the Theaetetus,
the Sophist, the Politicus, and the Laws, much as Universals would be
spoken of in modern books. Indeed, there are very faint traces of the
transcendental doctrine of Ideas, that is, of their existence apart from
the mind, in any of Plato's writings, with the exception of the Meno, the
Phaedrus, the Phaedo, and in portions of the Republic. The stereotyped
form which Aristotle has given to them is not found in Plato (compare Essay
on the Platonic Ideas in the Introduction to the Meno.)

The full discussion of this subject involves a comprehensive survey of the
philosophy of Plato, which would be out of place here. But, without
digressing further from the immediate subject of the Parmenides, we may
remark that Plato is quite serious in his objections to his own doctrines:
nor does Socrates attempt to offer any answer to them. The perplexities
which surround the one and many in the sphere of the Ideas are also alluded