n which passed whilst he slept
or thought not; yet, having observed the revolution of days and nights,
and found the length of their duration to be in appearance regular
and constant, he can, upon the supposition that that revolution has
proceeded after the same manner whilst he was asleep or thought not, as
it used to do at other times, he can, I say, imagine and make allowance
for the length of duration whilst he slept. But if Adam and Eve, (when
they were alone in the world,) instead of their ordinary night's sleep,
had passed the whole twenty-four hours in one continued sleep, the
duration of that twenty-four hours had been irrecoverably lost to them,
and been for ever left out of their account of time.

6. The Idea of Succession not from Motion.

Thus by reflecting on the appearing of various ideas one after another
in our understandings, we get the notion of succession; which, if any
one should think we did rather get from our observation of motion by
our senses, he will perhaps be of my mind when he considers, that even
motion produces in his mind an idea of succession no otherwise than as
it produces there a continued train of distinguishable ideas. For a man
looking upon a body really moving, perceives yet no motion at all unless
that motion produces a constant train of successive ideas: v.g. a man
becalmed at sea, out of sight of land, in a fair day, may look on the
sun, or sea, or ship, a whole hour together, and perceive no motion at
all in either; though it be certain that two, and perhaps all of them,
have moved during that time a great way. But as soon as he perceives
either of them to have changed distance with some other body, as soon as
this motion produces any new idea in him, then he perceives that there
has been motion. But wherever a man is, with all things at rest about
him, without perceiving any motion at all,--if during this hour of quiet
he has been thinking, he will perceive the various ideas of his own
thoughts in his own mind, appearing one after another, and thereby
observe and find succession where he could observe no motion.

7. Very slow motions unperceived.

And this, I think, is the reason why motions very slow, though they are
constant, are not perceived by us; because in their remove from one
sensible part towards another, their change of distance is so slow, that
it causes no new ideas in us, but a good while one after another. And
so not causing a constant train of new idea