rofesses to teach, in what manner a nation may be made rich. This
notion of what constitutes the science, is in some degree countenanced
by the title and arrangement which Adam Smith gave to his invaluable
work. A systematic treatise on Political Economy, he chose to call an
_Inquiry into the Nature and Causes of the Wealth of Nations_; and the
topics are introduced in an order suitable to that view of the purpose
of his book.

With respect to the definition in question, if definition it can be
called which is not found in any set form of words, but left to be
arrived at by a process of abstraction from a hundred current modes of
speaking on the subject; it seems liable to the conclusive objection,
that it confounds the essentially distinct, though closely connected,
ideas of _science_ and _art_. These two ideas differ from one another as
the understanding differs from the will, or as the indicative mood in
grammar differs from the imperative. The one deals in facts, the other
in precepts. Science is a collection of _truths_; art, a body of
_rules_, or directions for conduct. The language of science is, This is,
or, This is not; This does, or does not, happen. The language of art is,
Do this; Avoid that. Science takes cognizance of a _phenomenon_, and
endeavours to discover its _law_; art proposes to itself an _end_, and
looks out for _means_ to effect it.

If, therefore, Political Economy be a science, it cannot be a collection
of practical rules; though, unless it be altogether a useless science,
practical rules must be capable of being founded upon it. The science of
mechanics, a branch of natural philosophy, lays down the laws of motion,
and the properties of what are called the mechanical powers. The art of
practical mechanics teaches how we may avail ourselves of those laws and
properties, to increase our command over external nature. An art would
not be an art, unless it were founded upon a scientific knowledge of the
properties of the subject-matter: without this, it would not be
philosophy, but empiricism; [Greek: empeiria,] not [Greek: technae,] in
Plato's sense. Rules, therefore, for making a nation increase in wealth,
are not a science, but they are the results of science. Political
Economy does not of itself instruct how to make a nation rich; but
whoever would be qualified to judge of the means of making a nation
rich, must first be a political economist.

2. The definition most generally received among