RY connexion and dependence one upon another. Till a
man doth this in the primary and original notions of things, he builds
upon floating and uncertain principles, and will often find himself at a
loss.

CHAPTER XIV.

IDEA OF DURATION AND ITS SIMPLE MODES.

1. Duration is fleeting Extension.

There is another sort of distance, or length, the idea whereof we
get not from the permanent parts of space, but from the fleeting and
perpetually perishing parts of succession. This we call DURATION; the
simple modes whereof are any different lengths of it whereof we have
distinct ideas, as HOURS, DAYS, YEARS, &c., TIME and ETERNITY.

2. Its Idea from Reflection on the Train of our Ideas.

The answer of a great man, to one who asked what time was: Si non rogas
intelligo, (which amounts to this; The more I set myself to think of it,
the less I understand it,) might perhaps persuade one that time, which
reveals all other things, is itself not to be discovered. Duration,
time, and eternity, are, not without reason, thought to have something
very abstruse in their nature. But however remote these may seem from
our comprehension, yet if we trace them right to their originals, I
doubt not but one of those sources of all our knowledge, viz. sensation
and reflection, will be able to furnish us with these ideas, as clear
and distinct as many others which are thought much less obscure; and we
shall find that the idea of eternity itself is derived from the same
common original with the rest of our ideas.

3. Nature and origin of the idea of Duration.

To understand TIME and ETERNITY aright, we ought with attention to
consider what idea it is we have of DURATION, and how we came by it. It
is evident to any one who will but observe what passes in his own mind,
that there is a train of ideas which constantly succeed one another
in his understanding, as long as he is awake. Reflection on these
appearances of several ideas one after another in our minds, is that
which furnishes us with the idea of SUCCESSION: and the distance between
any parts of that succession, or between the appearance of any two ideas
in our minds, is that we call DURATION. For whilst we are thinking, or
whilst we receive successively several ideas in our minds, we know that
we do exist; and so we call the existence, or the continuation of the
existence of ourselves, or anything else, commensurate to the succession
of any ideas in our minds, the duration