have known by
his touch that a cube is a body terminated by square surfaces, and that a
sphere is not terminated by square surfaces: upon the supposition that a
visible and tangible square differ only IN NUMERO it follows that he
might know, by the unerring mark of the square surfaces, which was the
cube, and which not, while he only saw them. We must therefore allow
either that visible extension and figures are specifically distinct from
tangible extension and figures, or else that the solution of this problem
given by those two thoughtful and ingenious men is wrong.

134. Much more might be laid together in proof of the proposition I have
advanced: but what has been said is, if I mistake not, sufficient to
convince anyone that shall yield a reasonable attention: and as for those
that will not be at the pains of a little thought, no multiplication of
words will ever suffice to make them understand the truth, or rightly
conceive my meaning.

135. I cannot let go the above-mentioned problem without some reflexion
on it. It hath been evident that a man blind from his birth would not, at
first sight, denominate anything he saw by the names he had been used to
appropriate to ideas of touch, VID. sect. 106. Cube, sphere, table are
words he has known applied to things perceivable by touch, but to things
perfectly intangible he never knew them applied. Those words in their
wonted application always marked out to his mind bodies or solid things
which were perceived by the resistance they gave: but there is no
solidity, no resistance or protrusion, perceived by sight. In short, the
ideas of sight are all new perceptions, to which there be no names
annexed in his mind: he cannot therefore understand what is said to him
concerning them: and to ask of the two bodies he saw placed on the table,
which was the sphere, which the cube? were to him a question downright
bantering and unintelligible; nothing he sees being able to suggest to
his thoughts the idea of body, distance, or in general of anything he had
already known.

136. It is a mistake to think the same thing affects both sight and
touch. If the same angle or square which is the object of touch be also
the object of vision, what should hinder the blind man at first sight
from knowing it? For though the manner wherein it affects the sight be
different from that wherein it affected his touch, yet, there being
beside his manner or circumstance, which is new and unknown, the an