om
another. The process of recovery is no other than the ordinary law of
association, by which in daily life the sight of one thing or person
recalls another to our minds, and by which in scientific enquiry from
any part of knowledge we may be led on to infer the whole. It is also
argued that ideas, or rather ideals, must be derived from a previous
state of existence because they are more perfect than the sensible forms
of them which are given by experience. But in the Phaedo the doctrine
of ideas is subordinate to the proof of the immortality of the soul.
'If the soul existed in a previous state, then it will exist in a future
state, for a law of alternation pervades all things.' And, 'If the ideas
exist, then the soul exists; if not, not.' It is to be observed, both
in the Meno and the Phaedo, that Socrates expresses himself with
diffidence. He speaks in the Phaedo of the words with which he has
comforted himself and his friends, and will not be too confident that
the description which he has given of the soul and her mansions is
exactly true, but he 'ventures to think that something of the kind is
true.' And in the Meno, after dwelling upon the immortality of the
soul, he adds, 'Of some things which I have said I am not altogether
confident' (compare Apology; Gorgias). From this class of uncertainties
he exempts the difference between truth and appearance, of which he is
absolutely convinced.

In the Republic the ideas are spoken of in two ways, which though not
contradictory are different. In the tenth book they are represented as
the genera or general ideas under which individuals having a common name
are contained. For example, there is the bed which the carpenter makes,
the picture of the bed which is drawn by the painter, the bed existing
in nature of which God is the author. Of the latter all visible beds
are only the shadows or reflections. This and similar illustrations or
explanations are put forth, not for their own sake, or as an exposition
of Plato's theory of ideas, but with a view of showing that poetry and
the mimetic arts are concerned with an inferior part of the soul and a
lower kind of knowledge. On the other hand, in the 6th and 7th books
of the Republic we reach the highest and most perfect conception, which
Plato is able to attain, of the nature of knowledge. The ideas are now
finally seen to be one as well as many, causes as well as ideas, and to
have a unity which is the idea of good and the c