bjects: we must allow something to be perceived by the feeling; and
after an interval and motion of the hand or other organ of sensation,
another object of the touch to be met with; and upon leaving that,
another; and so on, as often as we please. The question is, whether
these intervals do not afford us the idea of extension without body?

To begin with the first case; it is evident, that when only two luminous
bodies appear to the eye, we can perceive, whether they be conjoined or
separate: whether they be separated by a great or small distance; and if
this distance varies, we can perceive its increase or diminution, with
the motion of the bodies. But as the distance is not in this case any
thing coloured or visible, it may be thought that there is here a vacuum
or pure extension, not only intelligible to the mind, but obvious to the
very senses.

This is our natural and most familiar way of thinking; but which we
shall learn to correct by a little reflection. We may observe, that
when two bodies present themselves, where there was formerly an entire
darkness, the only change, that is discoverable, is in the appearance
of these two objects, and that all the rest continues to be as before, a
perfect negation of light, and of every coloured or visible object. This
is not only true of what may be said to be remote from these bodies, but
also of the very distance; which is interposed betwixt them; that being
nothing but darkness, or the negation of light; without parts, without
composition, invariable and indivisible. Now since this distance causes
no perception different from what a blind man receives from his eyes, or
what is conveyed to us in the darkest night, it must partake of the
same properties: And as blindness and darkness afford us no ideas of
extension, it is impossible that the dark and undistinguishable distance
betwixt two bodies can ever produce that idea.

The sole difference betwixt an absolute darkness and the appearance of
two or more visible luminous objects consists, as I said, in the objects
themselves, and in the manner they affect our senses. The angles, which
the rays of light flowing from them, form with each other; the motion
that is required in the eye, in its passage from one to the other; and
the different parts of the organs, which are affected by them; these
produce the only perceptions, from which we can judge of the distance.
But as these perceptions are each of them simple and indivisi