ct to be a deduction from reason, drawn from
certain premises, whereas it seems to be an immediate perception; and
secondly, because all the premises from which this conclusion is
supposed to be drawn, are absolutely unknown to far the greater part
of mankind, and yet they all see objects erect.

Bishop Berkeley, who justly rejects this solution, gives another,
founded on his own principles, in which he is followed by Dr. Smith.
This ingenious writer thinks that the ideas of sight are altogether
unlike those of touch; and since the notions we have of an object by
these different senses, have no similitude, we can learn only by
experience how one sense will be affected, by what, in a certain
manner, affects the other. Thus, finding from experience, that an
object in an erect position, affects the eye in one manner, and that
the same object in an inverted position, affects it in another, we
learn to judge, by the manner in which the eye is affected, whether
the object is erect or inverted. But it is evident that Bishop
Berkeley proceeds upon a capital mistake, in supposing that there is
no resemblance between the extension, figure, and position, which we
see, and that which we perceive by touch. It may be further observed,
that Bishop Berkeley's system, with regard to material things, must
have made him see this question, in a very different light from that
in which it appears to those who do not adopt his system.

In order to give a satisfactory answer to this question, we must
first examine some of the laws of nature, which take place in vision;
for by these the phenomena of vision must be regulated.

It is now, I believe, pretty well established, as a law of nature,
that we see every point of an object in the direction of a right
line, which passes from the picture of that point on the retina,
through the centre of the eye. This beautiful law is proved by a very
copious induction of facts; the facts upon which it is founded are
taken from some curious experiments of Scheiner, in his Fundamenta
Optices. They are confirmed by Dr. Porterfield, and well illustrated
by Dr. Reid. The seeing objects erect by inverted images is a
necessary consequence of this law of nature: for from thence it is
evident that the point of the object whose picture is lowest on the
retina, must be seen in the highest direction from the eye; and that
the picture which is on the right side of the retina, must be seen on
the left.

_Of seeing O