erience. In the man of
the best sense and longest experience, this authority is never entire;
since even such-a-one must be conscious of many errors in the past, and
must still dread the like for the future. Here then arises a new species
of probability to correct and regulate the first, and fix its just
standard and proportion. As demonstration is subject to the controul of
probability, so is probability liable to a new correction by a reflex
act of the mind, wherein the nature of our understanding, and our
reasoning from the first probability become our objects.

Having thus found in every probability, beside the original uncertainty
inherent in the subject, a new uncertainty derived from the weakness of
that faculty, which judges, and having adjusted these two together,
we are obliged by our reason to add a new doubt derived from the
possibility of error in the estimation we make of the truth and fidelity
of our faculties. This is a doubt, which immediately occurs to us, and
of which, if we would closely pursue our reason, we cannot avoid giving
a decision. But this decision, though it should be favourable to our
preceding judgment, being founded only on probability, must weaken still
further our first evidence, and must itself be weakened by a fourth
doubt of the same kind, and so on in infinitum: till at last there
remain nothing of the original probability, however great we may
suppose it to have been, and however small the diminution by every new
uncertainty. No finite object can subsist under a decrease repeated IN
INFINITUM; and even the vastest quantity, which can enter into human
imagination, must in this manner be reduced to nothing. Let our first
belief be never so strong, it must infallibly perish by passing through
so many new examinations, of which each diminishes somewhat of its force
and vigour. When I reflect on the natural fallibility of my judgment,
I have less confidence in my opinions, than when I only consider the
objects concerning which I reason; and when I proceed still farther,
to turn the scrutiny against every successive estimation I make of my
faculties, all the rules of logic require a continual diminution, and at
last a total extinction of belief and evidence.

Should it here be asked me, whether I sincerely assent to this argument,
which I seem to take such pains to inculcate, and whether I be really
one of those sceptics, who hold that all is uncertain, and that our
judgment is not in