reason
can be assigned why we should pitch on one more than another: and except
there be some invariable, determinate extension fixed on to be marked to
the word inch, it is plain it can be used to little purpose; and to say a
thing contains this or that number of inches shall imply no more than
that it is extended, without bringing any particular idea of that
extension into the mind. Farther, an inch and a foot, from different
distances, shall both exhibit the same visible magnitude, and yet at the
same time you shall say that one seems several times greater than the
other. From all which it is manifest that the judgments we make of the
magnitude of objects by sight are altogether in reference to their
tangible extension. Whenever we say an object is great, or small, of this
or that determinate measure, I say it must be meant of the tangible, and
not the visible extension, which, though immediately perceived, is
nevertheless little taken notice of.

62. Now, that there is no necessary connexion between these two distinct
extensions is evident from hence: because our eyes might have been framed
in such a manner as to be able to see nothing but what were less than the
MINIMUM TANGIBILE. In which case it is not impossible we might have
perceived all the immediate objects of sight, the very same that we do
now: but unto those visible appearances there would not be connected
those different tangible magnitudes that are now. Which shows the
judgments we make of the magnitude of things placed at a distance from
the various greatness of the immediate objects of sight do not arise from
any essential or necessary but only a customary tie, which has been
observed between them.

63. Moreover, it is not only certain that any idea of sight might not
have been connected with this or that idea of touch, which we now observe
to accompany it: but also that the greater visible magnitudes might have
been connected with, and introduced into our minds lesser tangible
magnitudes and the lesser visible magnitudes greater tangible magnitudes.
Nay, that it actually is so we have daily experience; that object which
makes a strong and large appearance, not seeming near so great as
another, the visible magnitude whereof is much less, but more faint, and
the appearance upper, or which is the same thing painted lower on the
RETINA, which faintness and situation suggest both greater magnitude and
greater distance.

64. From which, and from sect.