11. Extension and body not the same.
There are some that would persuade us, that body and extension are the
same thing, who either change the signification of words, which I would not suspect them of,--they having so
severely condemned the philosophy of others, because it hath been too much placed in the uncertain meaning, or
deceitful obscurity of doubtful or insignificant terms. If, therefore, they mean by body and extension the same that
other people do, viz., by body something that is solid and extended, whose parts are separable and movable
different ways; and by extension, only the space that lies between the extremities of those solid coherent parts,
and which is possessed by them,--they confound very different ideas one with another; for I appeal to every
man's own thoughts whether the idea of space be not as distinct from that of solidity, as it is from the idea of
scarlet colour? It is true, solidity cannot exist without extension, neither can scarlet colour exist without extension,
but this hinders not, but that they are distinct ideas. Many ideas require others, as necessary to their existence or
conception, which yet are very distinct ideas. Motion can neither be, nor be conceived, without space; and yet
motion is not space, nor space motion; space can exist without it, and they are very distinct ideas; and so, I think,
are those of space and solidity. Solidity is so inseparable an idea from body, that upon that depends its filling of
space, its contact, impulse, and communication of motion upon impulse. And if it be a reason to prove that spirit
is different from body, because thinking includes not the idea of extension in it; the same reason will be as valid, I
suppose, to prove that space is not body, because it includes not the idea of solidity in it; space and solidity being
as distinct ideas as thinking and extension, and as wholly separable in the mind one from another. Body then and
extension, it is evident, are two distinct ideas. For,
