elves and by the
object; which must be multiplyd, in order to be conceivd at once, as
existent in these two different points of time: Or on the other hand,
we may trace the succession of time by a like succession of ideas,
and conceiving first one moment, along with the object then existent,
imagine afterwards a change in the time without any VARIATION or
INTERRUPTION in the object; in which case it gives us the idea of unity.
Here then is an idea, which is a medium betwixt unity and number; or
more properly speaking, is either of them, according to the view, in
which we take it: And this idea we call that of identity. We cannot, in
any propriety of speech, say, that an object is the same with itself,
unless we mean, that the object existent at one time is the same with
itself existent at another. By this means we make a difference, betwixt
the idea meant by the word, OBJECT, and that meant by ITSELF, without
going the length of number, and at the same time without restraining
ourselves to a strict and absolute unity.

Thus the principle of individuation is nothing but the INVARIABLENESS
and UNINTERRUPTEDNESS of any object, thro a supposd variation of
time, by which the mind can trace it in the different periods of its
existence, without any break of the view, and without being obligd to
form the idea of multiplicity or number.

I now proceed to explain the SECOND part of my system, and shew why
the constancy of our perceptions makes us ascribe to them a perfect
numerical identity, tho there be very long intervals betwixt their
appearance, and they have only one of the essential qualities of
identity, VIZ, INVARIABLENESS. That I may avoid all ambiguity and
confusion on this head, I shall observe, that I here account for the
opinions and belief of the vulgar with regard to the existence of body;
and therefore must entirely conform myself to their manner of thinking
and of expressing themselves. Now we have already observd, that however
philosophers may distinguish betwixt the objects and perceptions of the
senses; which they suppose co-existent and resembling; yet this is a
distinction, which is not comprehended by the generality of mankind, who
as they perceive only one being, can never assent to the opinion of a
double existence and representation. Those very sensations, which enter
by the eye or ear, are with them the true objects, nor can they
readily conceive that this pen or paper, which is immediately perceivd,