THE question which this Essay is concerned to put and
find some answer to is: What has present-day Psychology
to tell us about the Variety of Experience which expresses
itself in Plato's Doctrine of Ideas? The importance of
this question has been gradually brought home to me by
my perusal of various expositions of the Doctrine offered by
Plato-scholars in recent times. These expositions, however
informing and suggestive they may be in parts, in them-
selves, as expositions, seem to me to fall short of scientific
sufficiency because not controlled from the basis of Psycho-
logy. The literary evidence contained in Plato's Dialogues
and Aristotle's Criticisms ¹ is fully taken, but submitted to
the judgement of no court. The cardinal question is not
asked: What has present-day Psychology to tell us about
the Variety of Experience which expresses itself in the
Doctrine of Ideas? The Doctrine is treated as if it were
a 'past event' in the 'History of Philosophy' for deter-
mining the true nature of which there is such and such
documentary evidence which, if only marshalled in the
right way, is in itself conclusive. It is as if a com-
mentator on Thucydides should think it unnecessary to
submit the literary record of the Plague at Athens to the
judgement of present-day medical science in order to ascer-
tain from that authority what precisely the disease is
which his author is endeavouring to describe.

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