Its disconnexion from the complex of fact is a mere abstraction.

It is not the substratum of the factor, but the very factor itself as bared in thought.

Thus what is a mere procedure of mind in the translation of sense-awareness into discursive knowledge has been transmuted into a fundamental character of nature.

In this way matter has emerged as being the metaphysical substratum of its properties, and the course of nature is interpreted as the history of matter.
Plato and Aristotle found Greek thought preoccupied with the quest for the simple substances in terms of which the course of events could be expressed.

We may formulate this state of mind in the question, What is nature made of?
The answers which their genius gave to this question, and more particularly the concepts which underlay the terms in which they framed their answers, have determined the unquestioned presuppositions as to time, space and matter which have reigned in science.
In Plato the forms of thought are more fluid than in Aristotle, and therefore, as I venture to think, the more valuable.