which I confess myself one) who persuade
themselves they have clear and distinct ideas; and that they can think
on space, without anything in it that resists or is protruded by body.
This is the idea of pure space, which they think they have as clear
as any idea they can have of the extension of body: the idea of the
distance between the opposite parts of a concave superficies being
equally as clear without as with the idea of any solid parts between:
and on the other side, they persuade themselves that they have, distinct
from that of pure space, the idea of SOMETHING THAT FILLS SPACE, that
can be protruded by the impulse of other bodies, or resist their motion.
If there be others that have not these two ideas distinct, but confound
them, and make but one of them, I know not how men, who have the same
idea under different names, or different ideas under the same name, can
in that case talk with one another; any more than a man who, not being
blind or deaf, has distinct ideas of the colour of scarlet and the sound
of a trumpet, could discourse concerning scarlet colour with the blind
man I mentioned in another place, who fancied that the idea of scarlet
was like the sound of a trumpet.

6. What Solidity is.

If any one asks me, WHAT THIS SOLIDITY IS, I send him to his senses to
inform him. Let him put a flint or a football between his hands, and
then endeavour to join them, and he will know. If he thinks this not a
sufficient explication of solidity, what it is, and wherein it consists;
I promise to tell him what it is, and wherein it consists, when he tells
me what thinking is, or wherein it consists; or explains to me what
extension or motion is, which perhaps seems much easier. The simple
ideas we have, are such as experience teaches them us; but if, beyond
that, we endeavour by words to make them clearer in the mind, we shall
succeed no better than if we went about to clear up the darkness of a
blind man's mind by talking; and to discourse into him the ideas of
light and colours. The reason of this I shall show in another place.

CHAPTER V.

OF SIMPLE IDEAS OF DIVERS SENSES.

Ideas received both by seeing and touching.

The ideas we get by more than one sense are, of SPACE or EXTENSION,
FIGURE, REST, and MOTION. For these make perceivable impressions, both
on the eyes and touch; and we can receive and convey into our minds the
ideas of the extension, figure, motion, and rest of bodies, both by
seei