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 really can exist, as we are conscious it does, its parts must also exist; and in order to that, must be considered as coloured or tangible.
We have therefore no idea of space or extension, but when we regard it as an object either of our sight or feeling.
The same reasoning will prove, that the indivisible moments of time must be filled with some real object or existence, whose succession forms the duration, and makes it be conceivable by the mind.
SECT.IV.OBJECTIONS ANSWERED.
Our system concerning space and time consists of two parts, which are intimately connected together.

The first depends on this chain of reasoning.