more
difficult or absurd, than to apply the notion I have of the moving of a
shadow one hour to-day upon the sun-dial to the duration of something
last night, v. g. the burning of a candle, which is now absolutely
separate from all actual motion; and it is as impossible for the
duration of that flame for an hour last night to co-exist with any
motion that now is, or for ever shall be, as for any part of duration,
that was before the beginning of the world, to co exist with the motion
of the sun now. But yet this hinders not but that, having the IDEA of
the length of the motion of the shadow on a dial between the marks of
two hours, I can as distinctly measure in my thoughts the duration of
that candle-light last night, as I can the duration of anything that
does now exist: and it is no more than to think, that, had the sun shone
then on the dial, and moved after the same rate it doth now, the shadow
on the dial would have passed from one hour-line to another whilst that
flame of the candle lasted.

28. Our measures of Duration dependent on our ideas.

The notion of an hour, day, or year, being only the idea I have of the
length of certain periodical regular motions, neither of which motions
do ever all at once exist, but only in the ideas I have of them in my
memory derived from my senses or reflection; I can with the same ease,
and for the same reason, apply it in my thoughts to duration antecedent
to all manner of motion, as well as to anything that is but a minute or
a day antecedent to the motion that at this very moment the sun is in.
All things past are equally and perfectly at rest; and to this way
of consideration of them are all one, whether they were before the
beginning of the world, or but yesterday: the measuring of any duration
by some motion depending not at all on the REAL co-existence of that
thing to that motion, or any other periods of revolution, but the having
a clear IDEA of the length of some periodical known motion, or other
interval of duration, in my mind, and applying that to the duration of
the thing I would measure.

29. The Duration of anything need not be co-existent with the motion we
measure it by.

Hence we see that some men imagine the duration of of the world, from
its first existence to this present year 1689, to have been 5639 years,
or equal to 5639 annual revolutions of the sun, and others a great deal
more; as the Egyptians of old, who in the time of Alexander counted
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