Use and Mention

One of the cardinal principles of Set Theory is that a set cannot be a member of itself. On the other hand, the Extension of any linguistic term is the set of all objects to which the term applies. Hence, the Extension of 'term' is every word in language. But, 'term' is itself a word. Therefore, 'term' is a set which includes itself, apparently contradicting the Set Theory principle, and likewise for 'word', 'definition', and other expressions, even 'language' itself. The standard resolution of this apparent contradiction reflects the priorities of the Philosophers of Language who are confronted with it. As useful as the notion Extension is, and as central as Philosophy of Language is, to them, the resources of Set Theory are fundamental to their enterprise, so it is the principles of the latter that are least compromisable. Hence, the standard solution is to trace the problem to an equivocation in expressions like 'term' et al., the disambiguation of which is accomplished by distinguishing between the 'use' and the 'mention' of an expression, thereby preserving the distinction between Set and Member. But, the efficiency of this solution comes at the expense of obscuring an important capacity of Language--its potential self-relatedness. Such self-relatedness might be an inconvenience to those theories, but Philosophy of Language would be impossible without at least some homogeneity surviving the separation of Mention from Use.