12. By motions, external, and in our organism.
If then external objects be not united to our minds when they
produce ideas therein; and yet we perceive these original qualities in such of them as singly fall under our senses,
it is evident that some motion must be thence continued by our nerves, or animal spirits, by some parts of our
bodies, to the brains or the seat of sensation, there to produce in our minds the particular ideas we have of them.
And since the extension, figure, number, and motion of bodies of an observable bigness, may be perceived at a
distance by the sight, it is evident some singly imperceptible bodies must come from them to the eyes, and thereby
convey to the brain some motion; which produces these ideas which we have of them in us.
