erience. _Universalia in re_
were conceived by him as sufficiently explaining the genesis of
cognition without the postulation of any such _universalia extra rem_.

* * * * *

To the Platonic doctrine he offered the further objection that the
eternal forms of things which that doctrine affirmed and which it
declared to be represented in their ideal types were necessarily
impotential. There was no generative power in the pure activity of
Thought. If, therefore, the essentials of Reality were ideal, it
followed that they also were impotent, and incapable of causative
efficacy. The sensible world, however, was a fluent and perpetually
generated stream, which required some potent cause to uphold it.

The eternal Reality which sustained the world was for him an Energy
constantly generating the actual, and no conception which failed to
provide for this process of causative generation of the things of Sense
could in his view adequately account for the phenomena of Nature nor
consequently could constitute the system of science.

In this argument Aristotle undoubtedly expressed a profound truth, but
it may perhaps be admitted that he rather failed to appreciate fully
the difficulty which the Platonic doctrine was designed to meet--that,
namely, of providing some sort of common nexus or unifying principle by
which the validity of Knowledge could be maintained. For he had no
certain means of showing that the potent energy of Nature was unitary
and homogeneous.

He is frequently described as a sensationalist, but such a view is
certainly incorrect. This, however, may be admitted--that he sought the
essentials of Reality not in the Mind but in the Object. It may be
fairly claimed that to this extent he occupied common ground with the
sensationalists, in that he was an adherent of the _tabula rasa_ view of
the Mind, expressed in the maxim:--

_Nihil est in intellectu quod non fuit in sensu._

* * * * *

Plato and Aristotle may be taken as typical of the two principal
intellectual tendencies which have characterised all subsequent
speculation--the Platonist, he who finds in the constitution of the Mind
the eternal principles or at least the types of the eternal principles
of Reality; the Aristotelian, he for whom these seem to reside in the
object and, in the act of Cognition, are merely impressed upon,
transferred to, presented to, or otherwise introduced into or