— 178 —
The Ideas of Space and Body distinct.       §23. But the Question being here, whether the Idea of Space or
Extension, be the same with the Idea of Body, it is not necessary to prove
the real existence of a Vacuum, but the Idea of it; which ’tis plain
Men have, when they enquire and dispute, whether there be a
Vacuum or no? For if they had not the Idea of Space without Body,
they could not make a question about its existence: And if their
Idea of Body did not include in it something more than the bare Idea
of Space, they could have no doubt about the plenitude of the
World; and ’twould be as absurd to demand, whether there were
Space without Body, as whether there were Space without Space, or
Body without Body, since these were but different Names of the
same Idea.
Locke Hum II, 13, §23, p. 178