II. There is certainty of the existence of an external world.
III. The external world in relation to us, is only an extended being which affects us, and is subject to constant laws which we may determine.
IV. We have the idea of extension.
V. The idea of extension is excited by sensations, but it is not confounded with them.
VI. The idea of extension is the basis of all our cognitions of bodies.
VII. The idea of extension should not be confounded with the imaginary representation of extension.
VIII. An extended space which is nothing real, is an absurdity.
IX. Space is nothing real distinguished from the extension of bodies.
X. Where there are no bodies, there are no distances.
XI. Motion is the change of the positions of bodies among themselves.