branches of physical
science. The investigation of some of the circumstances which regulate
the price of corn, has as little to do with the laws common to the
production of all wealth, as any part of the knowledge of the
agriculturist. The inquiry into the rent of mines or fisheries, or into
the value of the precious metals, elicits truths which have immediate
reference to the production solely of a peculiar kind of wealth; yet
these are admitted to be correctly placed in the science of Political
Economy.

The real distinction between Political Economy and physical science must
be sought in something deeper than the nature of the subject-matter;
which, indeed, is for the most part common to both. Political Economy,
and the scientific grounds of all the useful arts, have in truth one and
the same subject-matter; namely, the objects which conduce to man's
convenience and enjoyment: but they are, nevertheless, perfectly
distinct branches of knowledge.

3. If we contemplate the whole field of human knowledge, attained or
attainable, we find that it separates itself obviously, and as it were
spontaneously, into two divisions, which stand so strikingly in
opposition and contradistinction to one another, that in all
classifications of our knowledge they have been kept apart. These are,
_physical_ science, and _moral_ or psychological science. The difference
between these two departments of our knowledge does not reside in the
subject-matter with which they are conversant: for although, of the
simplest and most elementary parts of each, it may be said, with an
approach to truth, that they are concerned with different subject-
matters--namely, the one with the human mind, the other with all things
whatever except the mind; this distinction does not hold between the
higher regions of the two. Take the science of politics, for instance,
or that of law: who will say that these are physical sciences? and yet
is it not obvious that they are conversant fully as much with matter as
with mind? Take, again, the theory of music, of painting, of any other
of the fine arts, and who will venture to pronounce that the facts they
are conversant with belong either wholly to the class of matter, or
wholly to that of mind?

The following seems to be the _rationale_ of the distinction between
physical and moral science.

In all the intercourse of man with nature, whether we consider him as
acting upon it, or as receiving impressions from it,