Locke on substance

In previous posts, I have argued that the semantics of individuation is object-independent.  To understand which individual is being discussed or mentioned does not depend on any relation between our mind and external reality. Real objects do not 'get through' to our understanding, and individual or singular thoughts remain the same whether or not there exist objects corresponding to them.

Someone will object that 'demonstrative reference' is the paradigm of true reference, and that demonstrative reference is necessarily dependent on objects.  We cannot understand the demonstrative 'this rose' without there being an actual rose that is pointed out.  The word 'demonstrate' is from the Latin demonstrare: to point out/at/to, draw attention to.  You cannot draw my attention to something, if there isn't a something.

Before I go on, I will  quote a famous passage from Locke*.  When we point to something, what is it we are pointing to?

Our obscure idea of substance in general. So that if any one will examine himself concerning his notion of pure substance in general, he will find he has no other idea of it at all, but only a supposition of he knows not what support of such qualities which are capable of producing simple ideas in us; which qualities are commonly called accidents. If any one should be asked, what is the subject wherein colour or weight inheres, he would have nothing to say, but the solid extended parts; and if he were demanded, what is it that solidity and extension adhere in, he would not be in a much better case than the Indian before mentioned who, saying that the world was supported by a great elephant, was asked what the elephant rested on; to which his answer was- a great tortoise: but being again pressed to know what gave support to the broad-backed tortoise, replied- something, he knew not what. And thus here, as in all other cases where we use words without having clear and distinct ideas, we talk like children: who, being questioned what such a thing is, which they know not, readily give this satisfactory answer, that it is something: which in truth signifies no more, when so used, either by children or men, but that they know not what; and that the thing they pretend to know, and talk of, is what they have no distinct idea of at all, and so are perfectly ignorant of it, and in the dark. The idea then we have, to which we give the general name substance, being nothing but the supposed, but unknown, support of those qualities we find existing, which we imagine cannot subsist sine re substante, without something to support them, we call that support substantia; which, according to the true import of the word, is, in plain English, standing under or upholding.

* Essay Concerning Human Understanding, II. xxxiii. 2.