de 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
circumstances, which from what I have formerly observed, determine me to
think that if I advance forward so many paces or miles, I shall be
affected with such and such ideas of touch: so that in truth and
strictness of speech I neither see distance itself, nor anything that I
take to be at a distance. I say, neither distance nor things placed at a
distance are themselves, or their ideas, truly perceived by sight. This I
am persuaded of, as to what concerns myself: and I believe whoever will
look narrowly into his own thoughts and examine what he means by saying
he sees this or that thing at a distance, will agree with me that what he
sees only suggests to his understanding that after having passed a
certain distance, to be measured by the motion of his body, which is
perceivable by touch, he shall come to perceive such and such tangible
ideas which have been usually connected with such and such visible ideas.
But that one might be deceived by these suggestions of sense, and that
there is no necessary connexion between visible and tangible ideas
suggested by them, we need go no farther than the next looking-glass or
pictures to be convinced. Note that when I speak of tangible ideas, I
take the word idea for any the immediate object of sense or
understanding, in which large signification it is commonly used by the
moderns.

46. From what we have shown it is a manifest consequence that the ideas
of space, outness, and things placed at a distance are not, strictly
speaking, the object of sight; they are not otherwise perceived by the
eye than by the ear. Sitting in my study I hear a coach drive along the
street; I look through the casement and see it; I walk out and enter into
it; thus, common speech would incline one to think I heard, saw, and
touched the same thing, to wit, the coach. It is nevertheless certain,
the ideas intromitted by each sense are widely different and distinct
from each other; but having been observed constantly to go together, they
are spoken of as one and the same thing. By the variation of the noise I
perceive the different distances of the coach, and know that it
approaches before I look out. Thus by the ear I perceive distance, just
after the same manner as I do by the eye.

47. I do not nevertheless say I