he sentiments or passions gives a sensible uneasiness,
whether it proceeds from without or from within; from the opposition
of external objects, or from the combat of internal principles. On the
contrary, whatever strikes in with the natural propensities, and either
externally forwards their satisfaction, or internally concurs with their
movements, is sure to give a sensible pleasure. Now there being here an
opposition betwixt the notion of the identity of resembling perceptions,
and the interruption of their appearance, the mind must be uneasy in
that situation, and will naturally seek relief from the uneasiness.
Since the uneasiness arises from the opposition of two contrary
principles, it must look for relief by sacrificing the one to the
other. But as the smooth passage of our thought along our resembling
perceptions makes us ascribe to them an identity, we can never without
reluctance yield up that opinion. We must, therefore, turn to the other
side, and suppose that our perceptions are no longer interrupted, but
preserve a continued as well as an invariable existence, and are by that
means entirely the same. But here the interruptions in the appearance
of these perceptions are so long and frequent, that it is impossible to
overlook them; and as the appearance of a perception in the mind and
its existence seem at first sight entirely the same, it may be doubted,
whether we can ever assent to so palpable a contradiction, and suppose a
perception to exist without being present to the mind. In order to clear
up this matter, and learn how the interruption in the appearance of a
perception implies not necessarily an interruption in its existence,
it will be proper to touch upon some principles, which we shall have
occasion to explain more fully afterwards. [Sect. 6.]

We may begin with observing, that the difficulty in the present case
is not concerning the matter of fact, or whether the mind forms such a
conclusion concerning the continued existence of its perceptions,
but only concerning the manner in which the conclusion is formed, and
principles from which it is derived. It is certain, that almost all
mankind, and even philosophers themselves, for the greatest part of
their lives, take their perceptions to be their only objects, and
suppose, that the very being, which is intimately present to the mind,
is the real body or material existence. It is also certain, that this
very perception or object is supposed to have