It is plain it is not the idea of extension. For the idea of extension
consists of parts; and this idea, according to t-he supposition, is
perfectly simple and indivisible. Is it therefore nothing? That is
absolutely impossible. For as the compound idea of extension, which is
real, is composed of such ideas; were these so many non-entities, there
would be a real existence composed of non-entities; which is absurd.
Here therefore I must ask, What is our idea of a simple and indivisible
point? No wonder if my answer appear somewhat new, since the question
itself has scarce ever yet been thought of. We are wont to dispute
concerning the nature of mathematical points, but seldom concerning the
nature of their ideas.

The idea of space is conveyed to the. mind by two senses, the sight and
touch; nor does anything ever appear extended, that is not either visible
or tangible. That compound impression, which represents extension,
consists of several lesser impressions, that are indivisible to the eye
or feeling, and may be called impressions of atoms or corpuscles endowed
with colour and solidity. But this is not all. It is not only requisite,
that these atoms should be coloured or tangible, in order to discover
themselves to our senses; it is also necessary we should preserve the idea
of their colour or tangibility in order to comprehend them by our
imagination. There is nothing but the idea of their colour or
tangibility, which can render them conceivable by the mind. Upon the
removal of the ideas of these sensible qualities, they are utterly
annihilated to the thought or imagination.

Now such as the parts are, such is the whole. If a point be not
considered as coloured or tangible, it can convey to us no idea; and
consequently the idea of extension, which is composed of the ideas of
these points, can never possibly exist. But if the idea of extension