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 ...

202 IDREAMING.
by Mr. Addison, (Spectator, No. 94,) from the Turkish Tales,
of the miracle wrought by a Mahometan doctor to convince an
infidel sultan, is, in such cases, nearly verified.
The facts I allude to at present are generally explained by
supposing, that, in our dreams, the rapidity of thought is greater
than while we are awake; but there is no necessity for having
recourse to such a supposition. The rapidity of thought is, at
all times, such, that in the twinkling of an eye a crowd of ideas
may pass before us, to which it would require a long discourse
to give utterance; and transactions may be conceived, which it
would require days to realize. But, in sleep, the conceptions
of the mind are mistaken for realities; and therefore our estimates of time will be formed, not according to our experience
of the rapidity of thought, but according to our experience of
the time requisite for realizing what we conceive. Something
perfectly analogous to this may be remarked in the perceptions
we obtain by the sense of sight. When I look into a show-box,
where the deception is imperfect, I see only a set of paltry
daubings of a few inches diameter; but if the representation
be executed with so much skill, as to convey to me the idea of
a distant prospect, every object before me swells in its dimensions, in proportion to the extent of space which I conceive it
to occupy; and what seemed before to be shut up within the
limits of a small wooden frame, is magnified, in my apprehension, to an immense landscape of woods, rivers, and mountains.
The phenomena of partial sleep. - The phenomena which we
have hitherto explained, take place when sleep seems to be
complete; that is, when the mind loses its influence over all
those powers whose exercise depends on its will. There are,
however, many cases in which sleep seems to be partial; that
is, when the mind loses its influence over some powers, and
retains it over others. In the case of the somnambuli, it retains
its power over the limbs, but it possesses no influence over its
own thoughts, and scarcely any over the body; excepting those
particular members of it which are employed in walking. In
madness, the power of the will over the body remains undiminished, while its influence in regulating the train of thought is