s, and of volition, in our
dreams renders the organs of sense liable to be more strongly affected by
the powers of sensation, and of association. For our desires or aversions,
or the obtrusions of surrounding bodies, dissever the sensitive and
associate tribes of ideas in our waking hours by introducing those of
irritation and volition amongst them. Hence proceeds the superior
distinctness of pleasurable or painful imagery in our sleep; for we recal
the figure and the features of a long lost friend, whom we loved, in our
dreams with much more accuracy and vivacity than in our waking thoughts.
This circumstance contributes to prove, that our ideas of imagination are
reiterations of those motions of our organs of sense, which were excited by
external objects; because while we are exposed to the stimuli of present
objects, our ideas of absent objects cannot be so distinctly formed.

11. The rapidity of the succession of transactions in our dreams is almost
inconceivable; insomuch that, when we are accidentally awakened by the
jarring of a door, which is opened into our bed-chamber, we sometimes dream
a whole history of thieves or fire in the very instant of awaking.

During the suspension of volition we cannot compare our other ideas with
those of the parts of time in which they exist; that is, we cannot compare
the imaginary scene, which is before us, with those changes of it, which
precede or follow it: because this act of comparing requires recollection
or voluntary exertion. Whereas in our waking hours, we are perpetually
making this comparison, and by that means our waking ideas are kept
confident with each other by intuitive analogy; but this companion retards
the succession of them, by occasioning their repetition. Add to this, that
the transactions of our dreams consist chiefly of visible ideas, and that a
whole history of thieves and fire may be _beheld_ in an instant of time
like the figures in a picture.

12. From this incapacity of attending to the parts of time in our dreams,
arises our ignorance of the length of the night; which, but from our
constant experience to the contrary, we should conclude was but a few
minutes, when our sleep is perfect. The same happens in our reveries; thus
when we are possessed with vehement joy, grief, or anger, time appears
short, for we exert no volition to compare the present scenery with the
past or future; but when we are compelled to perform those exercises of
mind or body