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 ...

34 EXTEInNAL PERCEiPTION.
dered, by reflection, sufficiently precise and satisfactory to show
them the absurdity of attempting to explain the mode of their
communication; had yet such a degree of influence on their
speculations, as to induce them to exhibit their supposed medium
under as mzysterious and ambiguous a form as possible, in order
that it might remain doubtful to which of the two predicaments,
of body or mind, they meant that it should be referred. By
refining away the grosser qualities of matter, and by allusions
to some of the most aerial and magical appearances it assumes,
they endeavored, as it were, to spiritualize the nature of their
medium; while at the same time, all their language concerning
it implied such a reference to matter, as was necessary for furnishing a plausible foundation for applying to it the received
maxims of natural philosophy.
Another observation, too, which was formerly hinted at, is
confirmed by the same historical review; that, in the order of
inquiry, the phenomena of vision had first engaged the attention
of philosophers, and had suggested to them the greater part of
their language with respect to perception in general; and that,
in consequence of this circumstance, the common modes of expression on the subject, unphilosophical and fanciful at best,
even when applied to the sense of seeing, are, in the case of all
the other senses, obviously unintelligible and self-contradictory.
As to objects of sight, says Dr. Reid, I understand what is
meant by an image of their figure in the brain; but how shall
we conceive an image of their color, where there is absolute
darkness? And, as to all other objects of sense, except figure
and color, I am unable to conceive what is meant by an image
of them. Let any man say, what he means by an image of
heat and cold, an image of hardness or softness, an image of
sound, or smell, or taste. The word image, when applied to these
objects of sense, has absolutely no meaning. This palpable imperfection in the ideal theory has plainly taken rise from the
natural order in which the phenomena of perception present
themselves to the curiosity.
That in the case of the perception of distant objects, we are
naturally inclined to suspect, either something to be emitted from