It is happy, therefore, that nature breaks the force of all sceptical arguments in time, and keeps them from having any considerable influence on the understanding.

Were we to trust entirely to their self-destruction, that can never take place, until they have first subverted all conviction, and have totally destroyed human reason.
SECT.II.OF SCEPTICISM WITH REGARD TO THE SENSES.
Thus the sceptic still continues to reason and believe, even though be asserts, that he cannot defend his reason by reason; and by the same rule he must assent to the principle concerning the existence of body, though he cannot pretend by any arguments of philosophy to maintain its veracity.

Nature has not left this to his choice, and has doubtless, esteemed it an affair of too great importance to be trusted to our uncertain reasonings and speculations.

We may well ask, What causes induce us to believe in the existence of body?
but it is in vain to ask, Whether there be body or not?
That is a point, which we must take for granted in all our reasonings.
The subject, then, of our present enquiry is concerning the causes which induce us to believe in the existence of body: And my reasonings on this head I shall begin with a distinction, which at first sight may seem superfluous, but which will contribute very much to the perfect understanding of what follows.

We ought to examine apart those two questions, which are commonly confounded together, viz.