The Concept of Nature | Page 8

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. Their importance
consists in the evidence they yield of cultivated thought about nature
before it had been forced into a uniform mould by the long tradition of
scientific philosophy. For example in the Timaeus there is a
presupposition, somewhat vaguely expressed, of a distinction between
the general becoming of nature and the measurable time of nature. In a
later lecture I have to distinguish between what I call the passage of
nature and particular time-systems which exhibit certain characteristics
of that passage. I will not go so far as to claim Plato in direct support of
this doctrine, but I do think that the sections of the Timaeus which deal
with time become clearer if my distinction is admitted.
This is however a digression. I am now concerned with the origin of the
scientific doctrine of matter in Greek thought. In the Timaeus Plato
asserts that nature is made of fire and earth with air and water as
intermediate between them, so that 'as fire is to air so is air to water,
and as air is to water so is water to earth.' He also suggests a molecular

hypothesis for these four elements. In this hypothesis everything
depends on the shape of the atoms; for earth it is cubical and for fire it
is pyramidal. To-day physicists are again discussing the structure of the
atom, and its shape is no slight factor in that structure. Plato's guesses
read much more fantastically than does Aristotle's systematic analysis;
but in some ways they are more valuable. The main outline of his ideas
is comparable with that of modern science. It embodies concepts which
any theory of natural philosophy must retain and in some sense must
explain. Aristotle asked the fundamental question, What do we mean
by 'substance'? Here the reaction between his philosophy and his logic
worked very unfortunately. In his logic, the fundamental type of
affirmative proposition is the attribution of a predicate to a subject.
Accordingly, amid the many current uses of the term 'substance' which
he analyses, he emphasises its meaning as 'the ultimate substratum
which is no longer predicated of anything else.'
The unquestioned acceptance of the Aristotelian logic has led to an
ingrained tendency to postulate a substratum for whatever is disclosed
in sense-awareness, namely, to look below what we are aware of for the
substance in the sense of the 'concrete thing.' This is the origin of the
modern scientific concept of matter and of ether, namely they are the
outcome of this insistent habit of postulation.
Accordingly ether has been invented by modern science as the
substratum of the events which are spread through space and time
beyond the reach of ordinary ponderable matter. Personally, I think that
predication is a muddled notion confusing many different relations
under a convenient common form of speech. For example, I hold that
the relation of green to a blade of grass is entirely different from the
relation of green to the event which is the life history of that blade for
some short period, and is different from the relation of the blade to that
event. In a sense I call the event the situation of the green, and in
another sense it is the situation of the blade. Thus in one sense the
blade is a character or property which can be predicated of the situation,
and in another sense the green is a character or property of the same
event which is also its situation. In this way the predication of
properties veils radically different relations between entities.

Accordingly 'substance,' which is a correlative term to 'predication,'
shares in the ambiguity. If we are to look for substance anywhere, I
should find it in events which are in some sense the ultimate substance
of nature.
Matter, in its modern scientific sense, is a return to the Ionian effort to
find in space and time some stuff which composes nature. It has a more
refined signification than the early guesses at earth and water by reason
of a certain vague association with the Aristotelian idea of substance.
Earth, water, air, fire, and matter, and finally ether are related in direct
succession so far as concerns their postulated characters of ultimate
substrata of nature. They bear witness to the undying vitality of Greek
philosophy in its