undamental distinction to remember is that
immediacy for sense-awareness is not the same as instantaneousness for
nature. This last conclusion bears on the next discussion with which I
will terminate this lecture. This question can be formulated thus, Can
alternative temporal series be found in nature?

A few years ago such a suggestion would have been put aside as being
fantastically impossible. It would have had no bearing on the science
then current, and was akin to no ideas which had ever entered into the
dreams of philosophy. The eighteenth and nineteenth centuries accepted
as their natural philosophy a certain circle of concepts which were as
rigid and definite as those of the philosophy of the middle ages, and
were accepted with as little critical research. I will call this natural
philosophy 'materialism.' Not only were men of science materialists, but
also adherents of all schools of philosophy. The idealists only differed
from the philosophic materialists on question of the alignment of nature
in reference to mind. But no one had any doubt that the philosophy of
nature considered in itself was of the type which I have called
materialism. It is the philosophy which I have already examined in my
two lectures of this course preceding the present one. It can be
summarised as the belief that nature is an aggregate of material and
that this material exists in some sense _at_ each successive member of a
one-dimensional series of extensionless instants of time. Furthermore
the mutual relations of the material entities at each instant formed
these entities into a spatial configuration in an unbounded space. It
would seem that space--on this theory--would be as instantaneous as the
instants, and that some explanation is required of the relations between
the successive instantaneous spaces. The materialistic theory is however
silent on this point; and the succession of instantaneous spaces is
tacitly combined into one persistent space. This theory is a purely
intellectual rendering of experience which has had the luck to get
itself formulated at the dawn of scientific thought. It has dominated
the language and the imagination of science since science flourished in
Alexandria, with the result that it is now hardly possible to speak
without appearing to assume its immediate obviousness.

But when it is distinctly formulated in the abstract terms in which I
have just stated it, the theory is very far from obvious. The passi