Substances was the question at issue in the famous controversy of the
later middle ages between Nominalism and Realism, which is one of the
turning points in the history of thought, being its first struggle to
emancipate itself from the dominion of verbal abstractions. The Realists
were the stronger party, but though the Nominalists for a time
succumbed, the doctrine they rebelled against fell, after a short
interval, with the rest of the scholastic philosophy. But while
universal substances and substantial forms, being the grossest kind of
realized abstractions, were the soonest discarded, Essences, Virtues,
and Occult Qualities long survived them, and were first completely
extruded from real existence by the Cartesians. In Descartes' conception
of science, all physical phaenomena were to be explained by matter and
motion, that is, not by abstractions but by invariable physical laws:
though his own explanations were many of them hypothetical, and turned
out to be erroneous. Long after him, however, fictitious entities (as
they are happily termed by Bentham) continued to be imagined as means of
accounting for the more mysterious phaenomena; above all in physiology,
where, under great varieties of phrase, mysterious _forces_ and
_principles_ were the explanation, or substitute for explanation, of the
phaenomena of organized beings. To modern philosophers these fictions
are merely the abstract names of the classes of phaenomena which
correspond to them; and it is one of the puzzles of philosophy, how
mankind, after inventing a set of mere names to keep together certain
combinations of ideas or images, could have so far forgotten their own
act as to invest these creations of their will with objective reality,
and mistake the name of a phaenomenon for its efficient cause. What was
a mystery from the purely dogmatic point of view, is cleared up by the
historical. These abstract words are indeed now mere names of
phaenomena, but were not so in their origin. To us they denote only the
phaenomena, because we have ceased to believe in what else they once