is the name given to that quality of matter
whereby two bodies cannot occupy the same space at the same time. The philosopher John Toland
argued that impenetrability and extension
were sufficient to define matter, a contention strongly disputed by Gottfried Wilhelm Von Leibniz
"Locke considered impenetrability to be ''"more a consequence of solidity, than solidity itself."
- Locke on Materialism
- An Essay Concerning Human Understanding (by Locke)
- Heinemann, F. H. "Toland and Leibniz." The Philosophical Review, Vol. 54, No. 5. (Sep., 1945), pp. 437-457.