1. G. Frege, “On Sense and Nominatum,” translated from the German by H. Feigl in Feigl and W. Sellars,Readings in Philosophical Analysis (New York: Appleton-Century-Crofts, 1949), pp. 85–102. All references to Frege will be to this work. A. Church is largely responsible for engendering contemporary interest in Frege's theory of meaning and naming. See, for example, his articles “Carnap's Introduction to Semantics,” Philosophical Review, 52:301–2, and “Descriptions,”The Dictionary of Philosophy, D. Runes, ed. (New York: Philosophical Library, 1942), p. 77.
2. We put in this qualification to exclude descriptions like “the man called ‘Aristotle’ ” which avoid the essential problem: What are the criteria on the basis of which a proper name is employed?
3. “Icon, Index, and Symbol,”Philosophy and Phenomenological Research, 9:673–39 Similar distinctions may be found in C. I. Lewis and C. H. Langford, Symbolic Logic (New York and London: Century, 1932), pp. 312ff; Bertrand Russell,An Inquiry into Meaning and Truth (London: G. Allen and Unwin, 1940), pp. 108ff; Nelson Goodman, The Structure of Appearance (Cambridge, Mass.: Harvard University Press, 1951); and H. Reichenbach, Elements of Symbolic Logic (New York: Macmillan, 1947), pp. 284ff.
4. The difference in meaning here referred to, and to be discussed in this section, is a difference in symbolic meaning (thus ‘P1’ differs from ‘P2’). One could also argue that there is a difference in indexical meaning (since the tokens of ‘this’ would occur at different times and places), but we shall not do so here. Cf. Burks, “Icon, Index, and Symbol,” pp. 681–82.
5. W. V. Quine,Methods of Logic (New York: Holt, 1950), pp. 210–11.