20

INTRODUCTION,

which collectively the expression political economy’
has been allotted, the first consideration is whether the
collection of the subjects is sufficiently complete, and
whether the knowledge we now possess of these subjects,
and of their inter-relations, suffices, to enable us to carry
back the generalizations of fact to the one elementary
fact antecedent to all of them, and thus to determine the
primal fact of the divisional science.
But supposing this cannot yet be done——that the
knowledge at present acquired is not sufficient to determine
 the primary basis; would such circumstance
necessarily prevent a scientific arrangement of the subjects?
 By no means; but it would prevent a complete
arrangement, even in outline, being made in the first
instance. To illustrate this, let us take the subjects of
chemical science. These were long since systematically
arranged as a science, although the ultimate generalization,
through which the actual basis of the divisional science
becomes apparent, has been, comparatively speaking,
quite recently made, and, even at the present time,
chemists can scarcely be said to have unanimously
accepted and recognized the fundamental fact of chemistry,
 as such.*
From this example and a knowledge of the progressive
advances by which chemistry, from a mere collection of
facts belonging to the same division, and having a general
connection in kind with each other, has become a comparatively
 complete divisional science, a distinct apprehension
 may be obtained of that approved method upon
which the scientific arrangement of the subjects belonging
 to other divisions of knowledge has to be conducted.
+ The Atomic Theory (of Dalton).