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 ...

ATTENTION. 49
monly called,) which would arise in his mind; for example, the
ideas of number, of duration, of cause and effect, of personal identity; all of which, though perfectly unlike his sensations, could.
not fail to be suggested by means of them. Such a being, then,
might know all that we know of mind at present; and as his
language would be appropriated to mind solely, and not borrowed
by analogy from material phenomena, he would even possess
important advantages over us in conducting the study of pneumatology.
From these observations it sufficiently appears, what is the
real amount of the celebrated doctrine, which refers the origin
of all our knowledge to our sensations; and that, even granting
it to be true, (which, for my own part, I am disposed to do, in
the sense in which I have now explained it,) it would by no
means follow from it, that our notions of the operations of mind,
nor even many of those notions which are commonly suggested
to us, in thefirst instance, by the perception of external objects,
are necessarily subsequent to our knowledge of the qualities, or
even of the existence, of matter.
CHA PTER I Lo
OF ATTENTION.
Attention necessary to memory, if not to perception. - When
we are deeply engaged in conversation, or occupied with any
speculation that is interesting to the mind, the surrounding objects either do not produce in us the perceptions they are fitted
to excite; or these perceptions are instantlyforgotten. A clock,
for example, may strike in the same room with us, without our
being able, next moment, to recollect whether we heard it or
not.
In these, and similar cases, I believe, it is commonly taken