total
suspense of judgment, and after what manner the mind ever retains a
degree of assurance in any subject? For as these new probabilities,
which by their repetition perpetually diminish the original evidence,
are founded on the very same principles, whether of thought or
sensation, as the primary judgment, it may seem unavoidable, that in
either case they must equally subvert it, and by the opposition,
either of contrary thoughts or sensations, reduce the mind to a total
uncertainty. I suppose, there is some question proposed to me, and
that after revolving over the impressions of my memory and senses,
and carrying my thoughts from them to such objects, as are commonly
conjoined with them, I feel a stronger and more forcible conception on
the one side, than on the other. This strong conception forms my first
decision. I suppose, that afterwards I examine my judgment itself,
and observing from experience, that it is sometimes just and sometimes
erroneous, I consider it as regulated by contrary principles or causes,
of which some lead to truth, and some to error; and in ballancing these
contrary causes, I diminish by a new probability the assurance of my
first decision. This new probability is liable to the same diminution as
the foregoing, and so on, IN INFINITUM. It is therefore demanded, how
it happens, that even after all we retain a degree of belief, which is
sufficient for our purpose, either in philosophy or common life.

I answer, that after the first and second decision; as the action of
the mind becomes forced and unnatural, and the ideas faint and obscure;
though the principles of judgment, and the ballancing of opposite
causes be the same as at the very beginning; yet their influence on the
imagination, and the vigour they add to, or diminish from the thought,
is by no means equal. Where the mind reaches not its objects with
easiness and facility, the same principles have not the same effect as
in a more natural conception of the ideas; nor does the imagination feel
a sensation, which holds any proportion with that which arises from
its common judgments and opinions. The attention is on the stretch: The
posture of the mind is uneasy; and the spirits being diverted from their
natural course, are not governed in their movements by the same laws, at
least not to the same degree, as when they flow in their usual channel.

If we desire similar instances, it will not be very difficult to find
them. The present