ABSTRACT
[W]hen we talk or think of any particular sort of corporeal Substances, as Horse, Stone, etc. though the Idea, we have of either of them, be but the Complication, or Collection of those several simple Ideas of sensible Qualities, which we find united in the thing called Horse or Stone, yet because we cannot conceive, how they should subsist alone, nor one in another, we suppose them existing in, and supported by some common subject; which Support we denote by the name Substance, though it be certain, we have no clear, or distinct Idea of that thing we suppose a Support. (John Locke, An Essay Concerning Human Understanding, Book II, Chapter XXIII, §4.)
