sorts of 'Idols of the Den': first, his own
Ideas, which he himself having created is unable to connect in any way
with the external world; secondly, against two idols in particular,
'Unity' and 'Being,' which had grown up in the pre-Socratic philosophy,
and were still standing in the way of all progress and development of
thought. He does not say with Bacon, 'Let us make truth by experiment,'
or 'From these vague and inexact notions let us turn to facts.' The time
has not yet arrived for a purely inductive philosophy. The instruments
of thought must first be forged, that they may be used hereafter by
modern inquirers. How, while mankind were disputing about universals,
could they classify phenomena? How could they investigate causes, when
they had not as yet learned to distinguish between a cause and an end?
How could they make any progress in the sciences without first arranging
them? These are the deficiencies which Plato is seeking to supply in an
age when knowledge was a shadow of a name only. In the earlier dialogues
the Socratic conception of universals is illustrated by his genius; in
the Phaedrus the nature of division is explained; in the Republic the
law of contradiction and the unity of knowledge are asserted; in the
later dialogues he is constantly engaged both with the theory and
practice of classification. These were the 'new weapons,' as he terms
them in the Philebus, which he was preparing for the use of some who, in
after ages, would be found ready enough to disown their obligations
to the great master, or rather, perhaps, would be incapable of
understanding them.

Numberless fallacies, as we are often truly told, have originated in a
confusion of the 'copula,' and the 'verb of existence.' Would not the
distinction which Plato by the mouth of Parmenides makes between 'One
is one' and 'One has being' have saved us from this and many similar
confusions? We see again that a long period in the history of philosophy
was a barren tract, not uncultivated, but unfruitful, because there
was no inquiry into the relation of language and thought, and the
metaphysical imagination was incapable of supplying the missing link
between words and things. The famous dispute between Nominalists and
Realists would never have been heard of, if, instead of transferring the
Platonic Ideas into a crude Latin phraseology, the spirit of Plato had
been truly understood and appreciated. Upon the term substance at least
two celebrat