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 ...

98 ABSTRACTION.
account which was given in a former chapter of th,omm, n
theories of perception, it appears to have been a prevailing
opinion among philosophers, that the qualities of external objects are perceived by means of images or species transmitted
to the mind by the organs of sense; an opinion of which I already endeavored to trace the origin, from certain natural prejudices suggested by the phenomena of the material world. The
samle train of thinking has led them to suppose, that, in the case
of all our other intellectual operations, there exist in the mind
certain ideas distinct from the mind itself; and that these ideas
are the objects about which our thoughts are employed. When
I recollect, for example, the appearance of an absent friend, it
is supposed that the immediate object of my thoughts is an idea
of my friend, which I at first received by my senses, and which
I have been enabled to retain in the mind by the faculty of
memory. When I form to myself any imaginary combination
by an effort of poetical invention, it is supposed, in like manner,
that the parts which I combine, existed previously in the mind,
and furnish the materials on which it is the province of imagination to operate. It is to Dr. Reid we owe the important remark, that all these notions are wholly hypothetical; that it is
impossible to produce a shadow of evidence in support of them;
and that, even although we were to admit their truth, they would
noot render the phenomena in question more intelligible. According to his principles, therefore, we have no ground for supposing, that, in any one operation of the mind, there exists in it
an object distinct from the mind itself; and all the common expressions which involve such a supposition, are to be considered
as unmeaning circumlocutions, which serve only to disguise
from us the real history of the intellectual phenomena.*
s In order to prevent misapprehensions of Dr. Reid's meaning in his rea.
sonings against the ideal theory, it may be necessary to explain, a little
more full) than I have done in the text, in what sense he calls in question
the existence of ideas; for the meaning which the word is employed to convey in popular discourse, differs widely from that which is annexed to it
by the philosophers whose opinion lie controverts. This explanation I
shall. give in his owin words: -