BOOK I PART II
tions are each of them simple and indivisible,
they can never give us the idea of extension.
We may illustrate this by considering the
sense of feeling, and the imaginary distance
or interval interposed betwixt tangible or solid
objects. I suppose two cases, viz. that of a man
supported in the air, and moving his limbs to
and fro, without meeting any thing tangible;
and that of a man, who feeling something tan-
gible, leaves it, and after a motion, of which
he is sensible, perceives another tangible object;
and I then ask, wherein consists the difference
betwixt these two cases? No one will make any
scruple to affirm, that it consists meerly in the
perceiving those objects, and that the sensation,
which arises from the motion, is in both cases
the same: And as that sensation is not capable
of conveying to us an idea of extension, when