59. Nor will it be found that great or small visible magnitude hath any
necessary relation to great or small tangible magnitude: so that the one
may certainly be inferred from the other. But before we come to the proof
of this, it is fit we consider the difference there is betwixt the
extension and figure which is the proper object of touch, and that other
which is termed visible; and how the former is principally, though not
immediately taken notice of, when we look at any object. This has been
before mentioned, but we shall here inquire into the cause thereof. We
regard the objects that environ us in proportion as they are adapted to
benefit or injure our own bodies, and thereby produce in our minds the
sensation of pleasure or pain. Now bodies operating on our organs, by an
immediate application, and the hurt or advantage arising therefrom,
depending altogether on the tangible, and not at all on the visible,
qualities of any object: this is a plain reason why those should be
regarded by us much more than these: and for this end the visive sense
seems to have been bestowed on animals, to wit, that by the perception of
visible ideas (which in themselves are not capable of affecting or any
wise altering the frame of their bodies) they may be able to foresee
(from the experience they have had what tangible ideas are connected with
such and such visible ideas) and damage or benefit which is like to
ensue, upon the application of their own bodies to this or that body
which is at a distance. Which foresight, how necessary it is to the
preservation of an animal, everyone's experience can inform him. Hence it
is that when we look at an object, the tangible figure and extension
thereof are principally attended to; whilst there is small heed taken of
the visible figure and magnitude, which, though more immediately
perceived, do less concern us, and are not fitted to produce any
alteration in our bodies.