of things placed at a distance, it is requisite that we look nearer into
the matter and carefully observe what is meant in common discourse, when
one says that which he sees is at a distance from him. Suppose, for
example, that looking at the moon I should say it were fifty or sixty
semidiameters of the earth distant from me. Let us see what moon this is
spoken of: it is plain it cannot be the visible moon, or anything like
the visible moon, or that which I see, which is only a round, luminous
plane of about thirty visible points in diameter. For in case I am
carried from the place where I stand directly towards the moon, it is
manifest the object varies, still as I go on; and by the time that I am
advanced fifty or sixty semidiameters of the earth, I shall be so far
from being near a small, round, luminous flat that I shall perceive
nothing like it; this object having long since disappeared, and if I
would recover it, it must be by going back to the earth from whence I set
out. Again, suppose I perceive by sight the faint and obscure idea of
something which I doubt whether it be a man, or a tree, or a tower, but
judge it to be at the distance of about a mile. It is plain I cannot mean
that what I see is a mile off, or that it is the image or likeness of
anything which is a mile off, since that every step I take towards it the
appearance alters, and from being obscure, small, and faint, grows clear,
large, and vigorous. And when I come to the mile's end, that which I saw
first is quite lost, neither do I find anything in the likeness of it.

45. In these and the like instances the truth of the matter stands thus:
having of a long time experienced certain ideas, perceivable by touch, as
distance, tangible figure, and solidity, to have been connected with
certain ideas of sight, I do upon perceiving these ideas of sight
forthwith conclude what tangible ideas are, by the wonted ordinary course
of Nature like to follow. Looking at an object I perceive a certain
visible figure and colour, with some degree of faintness and other