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 ...

194 DREAMING.
by availing itself of the established laws of association; but
still it has the power of rendering this train very different from
what it would have been, if these laws had taken place without
its interference.
How dreams would differ from waking thoughts upon this
theory. — From these principles, combined with the general
fact which I have endeavored to establish, with respect to the
state of the mind in sleep, two obvious consequences follow:
first, that when we are in this situation, the succession of our
thoughts, in so far as it depends on the laws of association,
may be carried on by the operation of the same unknown
causes by which it is produced while we are awake; and,
secondly, that the order of our thoughts, in these two states of
the mind, must be very different; inasmuch as, in the one, it
depends solely on the laws of association, and in the other, on
these laws combined with our own voluntary exertions.
In order to ascertain how far these conclusions are agreeable
to truth, it is necessary to compare them with the known
phenomena of dreaming. For which purpose, I shall endeavor
to show, first, that the succession of our thoughts in sleep, is
regulated by the same general laws of association, to which it
-is subjected while we are awake; and, secondly, that the
circumstances which discriminate dreaming from our waking
thoughts, are such as must necessarily arise from the suspension
of the influence of the will.
I. That the succession of our thoughts in sleep, is regulated by
the same general laws of association, which influence the mind
while we are awake, appears from the following considerations.
1. Our dreams are frequently suggested to us-by bodily sensations; and with these, it is well known, from what we experience
while awake, that particular ideas are frequently very strongly
associated. I have been told by a friend, that, having occasion,
in consequence of an indisposition, to apply a bottle of hot
water to his feet when he went to bed, he dreamed that he was
making a journey to the top of Mount _Etna, and that he found
the heat of the ground almost insupportable. Another person,
having a blister applied to his head, dreamed that he was