st we
dispute without understanding perfectly the subject of the controversy.
It is evident the idea of darkness is no positive idea, but merely the
negation of light, or more properly speaking, of coloured and visible
objects. A man, who enjoys his sight, receives no other perception from
turning his eyes on every side, when entirely deprived of light, than
what is common to him with one born blind; and it is certain such-a-one
has no idea either of light or darkness. The consequence of this is,
that it is not from the mere removal of visible objects we receive
the impression of extension without matter; and that the idea of utter
darkness can never be the same with that of vacuum.

Suppose again a man to be Supported in the air, and to be softly
conveyed along by some invisible power; it is evident he is sensible of
nothing, and never receives the idea of extension, nor indeed any idea,
from this invariable motion. Even supposing he moves his limbs to
and fro, this cannot convey to him that idea. He feels in that case a
certain sensation or impression, the parts of which are successive to
each other, and may give him the idea of time: But certainly are not
disposed in such a manner, as is necessary to convey the idea of space
or the idea of space or extension.

Since then it appears, that darkness and motion, with the utter removal
of every thing visible and tangible, can never give us the idea of
extension without matter, or of a vacuum; the next question is, whether
they can convey this idea, when mixed with something visible and
tangible?

It is commonly allowed by philosophers, that all bodies, which discover
themselves to the eye, appear as if painted on a plain surface, and that
their different degrees of remoteness from ourselves are discovered
more by reason than by the senses. When I hold up my hand before me, and
spread my fingers, they are separated as perfectly by the blue colour
of the firmament, as they coued be by any visible object, which I coued
place betwixt them. In order, therefore, to know whether the sight can
convey the impression and idea of a vacuum, we must suppose, that amidst
an entire darkness, there are luminous bodies presented to us, whose
light discovers only these bodies themselves, without giving us any
impression of the surrounding objects.

We must form a parallel supposition concerning the objects of our
feeling. It is not proper to suppose a perfect removal of all tangible
o