necessity of their coexistence, or without so much as knowing what it is
that makes them so to coexist. Of this there are innumerable instances of
which no one can be ignorant.

26. Thus, greater confusion having been constantly attended with nearer
distance, no sooner is the former IDEA perceived, but it suggests the
latter to our thoughts. And if it had been the ordinary course of Nature
that the farther off an OBJECT were placed, the more confused it should
appear, it is certain the very same perception that now makes us think an
OBJECT approaches would then have made us to imagine it went farther off.
That perception, abstracting from CUSTOM and EXPERIENCE, being equally
fitted to produce the IDEA of great distance, or small distance, or no
distance at all.

27. Thirdly, an OBJECT being placed at the distance above specified, and
brought nearer to the eye, we may nevertheless prevent, at least for some
time, the appearances growing more confused, by straining the eye. In
which case that sensation supplies the place of confused VISION in aiding
the mind to judge of the distance of the OBJECT; it being esteemed so
much the nearer by how much the effort or straining of the eye in order
to distinct VISION is greater.

28. I have here set down those sensations or IDEAS that seem to be the
constant and general occasions of introducing into the mind the different
IDEAS of near distance. It is true in most cases that divers other
circumstances contribute to frame our IDEA of distance, to wit, the
particular number, size, kind, etc., of the things seen. Concerning
which, as well as all other the forementioned occasions which suggest
distance, I shall only observe they have none of them, in their own
nature, any relation or connection with it: nor is it possible they should