ts
to no more than colours with their variations and different
proportions of light and shade; but the perpetual mutability
and fleetingness of those immediate objects of sight
render them incapable of being managed after the manner of
geometrical figures, nor is it in any degree useful that they
should. It is true there be divers of them perceived at once,
and more of some and less of others; but accurately to compute
their magnitude, and assign precise determinate proportions
between things so variable and inconstant, if we suppose
it possible to be done, must yet be a very trifling and
insignificant labour."

If, by this, Berkeley means that by vision alone, a straight line
cannot be distinguished from a curved one, a circle from a square,
a long line from a short one, a large angle from a small one, his
position is surely absurd in itself and contradictory to his own
previously cited admissions; if he only means, on the other hand, that
his pure spirit could not get very far on in his geometry, it may be
true or not; but it is in contradiction with his previous assertion,
that such a pure spirit could never attain to know as much as the
first elements of plane geometry.

Another source of confusion, which arises out of Berkeley's
insufficient exactness in the use of language, is to be found in what
he says about solidity, in discussing Molyneux's problem, whether a
man born blind and having learned to distinguish between a cube and a
sphere, could, on receiving his sight, tell the one from the other
by vision. Berkeley agrees with Locke that he could not, and adds the
following reflection:--

"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."

Here "solidity" means resistance to pressure, which is apprehended by
the muscular sense; but when in section 154 Berkeley says of his pure
intelligence--

"It is certain that the aforesaid intelligence could have no
idea of a solid or quantity of three dimensions, which follows
from its not having any idea of distance "--

he refers to that notion of solidity which may be ob