an identity to them.
Thirdly, Account for that propensity, which this illusion gives, to
unite these broken appearances by a continued existence. Fourthly and
lastly, Explain that force and vivacity of conception, which arises from
the propensity.

First, As to the principle of individuation; we may observe, that the
view of any one object is not sufficient to convey the idea of identity.
For in that proposition, an object is the same with itself, if the idea
expressed by the word, object, were no ways distinguished from
that meant by itself; we really should mean nothing, nor would the
proposition contain a predicate and a subject, which however are implyed
in this affirmation. One single object conveys the idea of unity, not
that of identity.

On the other hand, a multiplicity of objects can never convey this idea,
however resembling they may be supposed. The mind always pronounces the
one not to be the other, and considers them as forming two, three,
or any determinate number of objects, whose existences are entirely
distinct and independent.

Since then both number and unity are incompatible with the relation of
identity, it must lie in something that is neither of them. But to tell
the truth, at first sight this seems utterly impossible. Betwixt unity
and number there can be no medium; no more than betwixt existence and
nonexistence. After one object is supposed to exist, we must either
suppose another also to exist; in which case we have the idea of number:
Or we must suppose it not to exist; in which case the first object
remains at unity.

To remove this difficulty, let us have recourse to the idea of time or
duration. I have already observd [Part II, Sect. 5.], that time, in a
strict sense, implies succession, and that when we apply its idea to
any unchangeable object, it is only by a fiction of the imagination, by
which the unchangeable object is supposd to participate of the
changes of the co-existent objects, and in particular of that of our
perceptions. This fiction of the imagination almost universally takes
place; and it is by means of it, that a single object, placd before us,
and surveyd for any time without our discovering in it any interruption
or variation, is able to give us a notion of identity. For when we
consider any two points of this time, we may place them in different
lights: We may either survey them at the very same instant; in which
case they give us the idea of number, both by thems