he dialectical
developments of ethics; by tracing concretions in existence it has
reached the various natural and historical sciences. Following ancient
usage, I shall take the liberty of calling the whole group of sciences
which elaborates ideas _dialectic_, and the whole group that describes
existences _physics_.

The contrast between ideal science or dialectic and natural science or
physics is as great as the understanding of a single experience could
well afford; yet the two kinds of science are far from independent. They
touch at their basis and they co-operate in their results. Were
dialectic made clearer or physics deeper than it commonly is, these
points of contact would doubtless be multiplied; but even as they stand
they furnish a sufficient illustration of the principle that all science
develops objects in their own category and gives the mind dominion over
the flux of matter by discovering its form.

[Sidenote: Their mutual implication.]

That physics and dialectic touch at their basis may be shown by a double
analysis. In the first place, it is clear that the science of existence,
like all science, is itself discourse, and that before concretions in
existence can be discovered, and groups of coexistent qualities can be
recognised, these qualities themselves must be arrested by the mind,
noted, and identified in their recurrences. But these terms, bandied
about in scientific discourse, are so many essences and pure ideas: so
that the inmost texture of natural science is logical, and the whole
force of any observation made upon the outer world lies in the constancy
and mutual relations of the terms it is made in. If down did not mean
down and motion motion, Newton could never have taken note of the fall
of his apple. Now the constancy and relation of meanings is something
_meant_, it is something created by insight and intent and is altogether
dialectical; so that the science of existence is a portion of the art of
discourse.

On the other hand discourse, in its operation, is a part of existence.
That truth or logical cogency is not itself an existence can be proved
dialectically,[A] and is obvious to any one who sees for a moment what
truth means, especially if he remembers at the same time that all
existence is mutable, which it is the essence of truth not to be. But
the knowledge or discovery of truth is an event in time, an incident in
the flux of existence, and therefore a matter for natural science