Let us, then, lend our attention to the examination of the idea of solidity.
The idea of solidity is that of two objects, which being impelled by the utmost force, cannot penetrate each other; but still maintain a separate and distinct existence.

Solidity, therefore, is perfectly incomprehensible alone, and without the conception of some bodies, which are solid, and maintain this separate and distinct existence.

Now what idea have we of these bodies?
The ideas of colours, sounds, and other secondary qualities are excluded.

The idea of motion depends on that of extension, and the idea of extension on that of solidity.

It is impossible, therefore, that the idea of solidity can depend on either of them.