¹ They will be thinking of Frege's discussion of how it is possible for a statement of identity to be informative in Frege, 's ‘On Sense and Meaning’ in Geach, Peter and Black, Max (eds), Translations from the Philosophical Writings of Gottlob Frege (Oxford: Blackwell, 1952), third edition, pp. 56–78.Google Scholar

² Frege talks of Gleichheit (=‘equality’) but he says in a footnote that he uses this word in the sense of Identität (=‘identity’) (Frege, , ‘On Sense and Meaning’, p. 56).Google Scholar

³ Op. cit., p. 56.

⁴ The English translation by Max Black of Frege's die Art des Gegebenseins as ‘mode of presentation’ is too high-flown: it loses, to no advantage, the natural simplicity of Frege's German in his example in which the single point of intersection of three straight lines in a geometrical figure is given as we say both in German and in English, in several different ways by means of different pairs of coordinates (Frege, , ‘On Sense and Meaning’, p. 57).Google Scholar

⁵ Quine, W. V., Quiddities: an Intermittently Philosophical Dictionary (Cambridge, Mass, and London, England: The Belnap Press of Harvard University Press, 1987), p. 89.Google Scholar

⁶ On the feeling, which evidently Quine shares, that the identity of a thing with itself provides us with an infallible paradigm of identity see Wittgenstein, Ludwig, Philosophical Investigations, remarks 215–6.Google Scholar

⁷ Frege, , ‘On Sense and Meaning’, p. 59.Google Scholar

⁸ Quoted in Quine, , Quiddities, p. 232.Google Scholar

⁹ The alleged use-mention confusion in Leibniz's various formulations of his law is sympathetically discussed in Mates, Benson, The Philosophy of Leibniz: Metaphysics and Language (New York and Oxford: Oxford University Press, 1986), pp. 123–30.Google Scholar