nd vegetables; where not
only the several parts have a reference to some general purpose, but
also a mutual dependence on, and connexion with each other. The effect
of so strong a relation is, that though every one must allow, that in a
very few years both vegetables and animals endure a total change, yet we
still attribute identity to them, while their form, size, and substance
are entirely altered. An oak, that grows from a small plant to a large
tree, is still the same oak; though there be not one particle of matter,
or figure of its parts the same. An infant becomes a man-, and is
sometimes fat, sometimes lean, without any change in his identity.

We may also consider the two following phaenomena, which are remarkable
in their kind. The first is, that though we commonly be able to
distinguish pretty exactly betwixt numerical and specific identity, yet
it sometimes happens, that we confound them, and in our thinking and
reasoning employ the one for the other. Thus a man, who bears a noise,
that is frequently interrupted and renewed, says, it is still the same
noise; though it is evident the sounds have only a specific identity or
resemblance, and there is nothing numerically the same, but the cause,
which produced them. In like manner it may be said without breach of the
propriety of language, that such a church, which was formerly of brick,
fell to ruin, and that the parish rebuilt the same church of free-stone,
and according to modern architecture. Here neither the form nor
materials are the same, nor is there any thing common to the two
objects, but their relation to the inhabitants of the parish; and yet
this alone is sufficient to make us denominate them the same. But
we must observe, that in these cases the first object is in a manner
annihilated before the second comes into existence; by which means, we
are never presented in any one point of time with the idea of difference
and multiplicity: and for that reason are less scrupulous in calling
them the same.

Secondly, We may remark, that though in a succession of related objects,
it be in a manner requisite, that the change of parts be not sudden nor
entire, in order to preserve the identity, yet where the objects are
in their nature changeable and inconstant, we admit of a more sudden
transition, than would otherwise be consistent with that relation. Thus
as the nature of a river consists in the motion and change of parts;
though in less than four and twenty