— 604 —
Instance in Vacuum.
      §13. But if another shall come, and make to himself another
Idea, different from Des-Cartes’s of the thing, which yet, with Des-
Cartes he calls by the same name Body, and make his Idea, which he
expresses by the word Body, to be of a thing that hath both Exten-
sion and Solidity together, he will as easily demonstrate, that there
may be a Vacuum, or Space without a Body, as Des-Cartes demon-
strated the contrary. Because the Idea to which he gives the name
Space, being barely the simple one of Extension; and the Idea, to
which he gives the name Body, being the complex Idea of Extension
and Resistibility, or Solidity together in the same subject, these two
Ideas are not exactly one and the same, but in the Understanding as
distinct as the Ideas of One and Two, White and Black, or as of
Corporeity and Humanity, if I may use those barbarous Terms: And
— 605 —
therefore the Predication of them in our Minds, or in Words
standing for them is not identical, but the Negation of them one
of another; viz. this Proposition Extension or Space is not Body, is as
true and evidently certain, as this Maxim, It is impossible for the
same thing to be, and not to be, can make any Proposition.
Locke Hum IV, 7, §13, pp. 604-605