To divide and separate actually is, as I think, by removing the parts one from another, to make two superficies, where before there was a continuity: and to divide mentally is, to make in the mind two superficies, where before there was a continuity, and consider them as removed one from the other; which can only be done in things considered by the mind as capable of being separated; and by separation, of acquiring new distinct superficies, which they then have not, but are capable of.