Elements of the philosophy of the human mind. By Dugald Stewart. Rev. and abridged, with critical and explanatory notes, for the use of colleges and schools. By Francis Bowen ...

ABSTRACTION. 95
by the name of abstraction. It has been supposed, by some philosophers, (with what probability I shall not now inquire,) to
form the characteristical attribute of a rational nature. That it
is one of the most important of all our faculties, and very intimnately connected with the exercise of our reasoning powers, is
beyond dispute.
Usefulness of the power of abstraction. - The subserviency of
abstraction to the power of reasoning, and also its subserviency
to the exertions of a poetical or creative imagination, shall be
afterwards fully illustrated. At present, it is sufficient for my
purpose to remark, that as abstraction is the groundwork of
classification, without this faculty of the mind we should have
been perfectly incapable of general speculation, and all our
knowledge must necessarily have been limited to individuals;
and that some of the most useful branches of science, particularly the different branches of mathematics, in which the very
subjects of our reasoning are abstractions of the understanding,
could never have possibly had an existence. With respect to
the subserviency of this faculty to poetical imagination, it is no
less obvious, that, as the poet is supplied with all his materials
by experience, and as his province is limited to combine and
modify things which really exist, so as to produce new wholes
of his own; so, every exertion which he thus makes of his powers, presupposes the exercise of abstraction in decomposing and
separating actual combinations. And it was on this account
that, in the chapter on conception, I was led to make a distinction between that faculty, which is evidently simple and uncompounded, and the power of imagination, which (at least in the
sense in which I employ the word in these inquiries) is the result of a combination of various other powers.
I have introduced these remarks, in order to point out a difference between the abstractions which are subservient to reasoning, and those which are subservient to imagination. And,
if I am not mistaken, it is a distinction which has not been sufficiently attended to by some writers of eminence. In every
instance in which imagination is employed in forming new
wholes, by decompounding and combining the conceptions of