leave all physical questions pending, as his master had done. He
adopted, accordingly, Heraclitus's doctrine of the immediate, which he
now called the realm of phenomena; for what exists at any instant, if
you arrest and name it, turns out to have been an embodiment of some
logical essence, such as discourse might define; in every fact some idea
makes its appearance, and such an apparition of the ideal is a
phenomenon. Moreover, another philosophy had made a deep impression on
Plato's mind and had helped to develop Socratic definitions: Parmenides
had called the concept of pure Being the only reality; and to satisfy
the strong dialectic by which this doctrine was supported and at the
same time to bridge the infinite chasm between one formless substance
and many appearances irrelevant to it, Plato substituted the many
Socratic ideas, all of which were relevant to appearance, for the one
concept of Parmenides. The ideas thus acquired what is called
metaphysical subsistence; for they stood in the place of the Eleatic
Absolute, and at the same time were the realities that phenomena
manifested.

The technique of this combination is much to be admired; but the feat is
technical and adds nothing to the significance of what Plato has to say
on any concrete subject. This barren triumph was, however, fruitful in
misunderstandings. The characters and values a thing possessed were now
conceived to subsist apart from it, and might even have preceded it and
caused its existence; a mechanism composed of values and definitions
could thus be placed behind phenomena to constitute a substantial
physical world. Such a dream could not be taken seriously, until good
sense was wholly lost and a bevy of magic spirits could be imagined
peopling the infinite and yet carrying on the business of earth.
Aristotle rejected the metaphysical subsistence of ideas, but thought
they might still be essences operative in nature, if only they were