conception of time; which since it, appears not as any primary distinct
impression, can plainly be nothing but different ideas, or impressions,
or objects disposed in a certain manner, that is, succeeding each other.

I know there are some who pretend, that the idea of duration is
applicable in a proper sense to objects, which are perfectly
unchangeable; and this I take to be the common opinion of philosophers as
well as of the vulgar. But to be convinced of its falsehood we need but
reflect on the foregoing conclusion, that the idea of duration is always
derived from a succession of changeable objects, and can never be
conveyed to the mind by any thing stedfast and unchangeable. For it
inevitably follows from thence, that since the idea of duration cannot be
derived from such an object, it can never-in any propriety or exactness
be applied to it, nor can any thing unchangeable be ever said to have
duration. Ideas always represent the Objects or impressions, from which
they are derived, and can never without a fiction represent or be applied
to any other. By what fiction we apply the idea of time, even to what is
unchangeable, and suppose, as is common, that duration is a measure of
rest as well as of motion, we shall consider [Sect 5.] afterwards.

There is another very decisive argument, which establishes the present
doctrine concerning our ideas of space and time, and is founded only on
that simple principle, that our ideas of them are compounded of parts,
which are indivisible. This argument may be worth the examining.

Every idea, that is distinguishable, being also separable, let us take
one of those simple indivisible ideas, of which the compound one of
extension is formed, and separating it from all others, and considering
it apart, let us form a judgment of its nature and qualities.