Page 196 of 1391

The most certain and necessary truth was to Plato the universal;

and to this he was always seeking to refer all knowledge or

opinion, just as in modern times we seek to rest them on the

opposite pole of induction and experience. The aspirations of

metaphysicians have always tended to pass beyond the limits of

human thought and language: they seem to have reached a height at

which they are 'moving about in worlds unrealized,' and their

conceptions, although profoundly affecting their own minds,

become invisible or unintelligible to others. We are not

therefore surprized to find that Plato himself has nowhere

clearly explained his doctrine of ideas; or that his school in a

later generation, like his contemporaries Glaucon and Adeimantus,

were unable to follow him in this region of speculation.