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 ...

80 CONCEPTION.
so, I apprehend, we cannot at one instant form a conception of
the whole of any visible object; but that our conception of
the object as a whole, is the result of many conceptions. The
association of ideas connects the different parts together, and
presents them to the mind in their proper arrangement; and
the various relations which these parts bear to one another in
point of situation, contribute greatly to strengthen the associations. It is some confirmation of this theory, that it is more
easy to remember a succession of sounds, than any particular
sound which we have heard detached and unconnected.
The power of conceiving visible objects, like all other powers
that depend on the association of ideas, may be wonderfully
improved by habit. A person accustomed to drawing retains
a much more perfect notion of a building or of a landscape
which he has seen, than one who has never practised that art.
A portrait painter traces the form of the human body from
memory, with as little exertion of attention, as he employs in
writing the letters which compose his name.
In the power of conceiving colors, too, there are striking differences among individuals: and, indeed, I am inclined to suspect, that, in the greater number of instances, the supposed
defects of sight in this respect ought to be ascribed rather to a
defect in the power of conception. One thing is certain, that
we often see men who are perfectly sensible of the difference
between two colors when they are presented to them, who cannot give names to these colors, with confidence, when they see
them apart; and are perhaps apt to confound the one with the
other. Such men, it should seem, feel the sensation of color
like other men, when the object is present, but are incapable
(probably in consequence of some early habit of inattention) to
conceive the sensation distinctly when the object is removed.
Without this power of conception, it is evidently impossible for
them, however lively their sensations may be, to give a name
to any color; for the application of the name supposes not only
a capacity of receiving the sensation, but a power of comparing
it with one formerly felt. At the same time, I would not be
understood by these observations to deny, that there are cases,