and colours other far different ideas are suggested to my mind: but so
they are by hearing, which beside sounds which are peculiar to that
sense, doth by their mediation suggest not only space, figure, and
motion, but also all other ideas whatsoever that can be signified by
words.

131. THIRDLY, it is, I think, an axiom universally received that
quantities of the same kind may be added together and make one entire
sum. Mathematicians add lines together: but they do not add a line to a
solid, or conceive it as making one sum with a surface: these three kinds
of quantity being thought incapable of any such mutual addition, and
consequently of being compared together in the several ways of
proportion, are by then esteemed entirely disparate and heterogeneous.
Now let anyone try in his thoughts to add a visible line or surface to a
tangible line or surface, so as to conceive them making one continued sum
or whole. He that can do this may think them homogeneous: but he that
cannot, must by the foregoing axiom think them heterogeneous. A blue and
a red line I can conceive added together into one sum and making one
continued line: but to make in my thoughts one continued line of a
visible and tangible line added together is, I find, a task far more
difficult, and even insurmountable: and I leave it to the reflexion and
experience of every particular person to determine for himself.

132. A farther confirmation of our tenet may be drawn from the solution
of Mr. Molyneux's problem, published by Mr. Locke in his ESSAY: which I
shall set down as it there lies, together with Mr. Locke's opinion of it,
'"Suppose a man born blind, and now adult, and taught by his touch to
distinguish between a cube and a sphere of the same metal, and nighly
[SIC] of the same bigness, so as to tell, when he felt one and t'other,
which is the cube and which the sphere. Suppose then the cube and sphere