these objects; this is what
we can never observe in them, but must draw the idea of it from what we
feel internally in contemplating them. And this I carry so far, that I
am ready to convert my present reasoning into an instance of it, by a
subtility, which it will not be difficult to comprehend.

When any object is presented to us, it immediately conveys to the mind
a lively idea of that object, which is usually found to attend it; and
this determination of the mind forms the necessary connexion of these
objects. But when we change the point of view, from the objects to the
perceptions; in that case the impression is to be considered as the
cause, and the lively idea as the effect; and their necessary connexion
is that new determination, which we feel to pass from the idea of the
one to that of the other. The uniting principle among our internal
perceptions is as unintelligible as that among external objects, and
is not known to us any other way than by experience. Now the nature
and effects of experience have been already sufficiently examined and
explained. It never gives us any insight into the internal structure or
operating principle of objects, but only accustoms the mind to pass from
one to another.

It is now time to collect all the different parts of this reasoning,
and by joining them together form an exact definition of the relation of
cause and effect, which makes the subject of the present enquiry. This
order would not have been excusable, of first examining our inference
from the relation before we had explained the relation itself, had it
been possible to proceed in a different method. But as the nature of the
relation depends so much on that of the inference, we have been obliged
to advance in this seemingly preposterous manner, and make use of terms
before we were able exactly to define them, or fix their meaning. We
shall now correct this fault by giving a precise definition of cause and
effect.

There may two definitions be given of this relation, which are only
different, by their presenting a different view of the same object,
and making us consider it either as a philosophical or as a natural
relation; either as a comparison of two ideas, or as an association
betwixt them. We may define a CAUSE to be An object precedent and
contiguous to another, and where all the objects resembling the former
are placed in like relations of precedency and contiguity to those
objects that resemble the latter. I