 A crucial consideration when individuating mental symbols is what role to assign to semantic properties. Here we may usefully compare Mentalese with natural language. It is widely agreed that natural language words do not have their denotations essentially. The English word “cat” denotes cats, but it could just as well have denoted dogs, or the number 27, or anything else, or nothing at all, if our linguistic conventions had been different. Virtually all contemporary LOT theorists hold that a Mentalese word likewise does not have its denotation essentially. The Mentalese word cat denotes cats, but it could have had a different denotation had it born different causal relations to the external world or had it occupied a different role in mental activity. In that sense, cat is a piece of formal syntax. Fodor’s early view (1981: 225–253) was that a Mentalese word could have had a different denotation but not an arbitrarily different denotation: cat could not have denoted just anything—it could not have denoted the number 27—but it could have denoted some other animal species had the thinker suitably interacted with that species rather than with cats. Fodor eventually (1994, 2008) embraces the stronger thesis that a Mentalese word bears an arbitrary relation to its denotation: cat could have had any arbitrarily different denotation. Most contemporary theorists agree (Egan 1992: 446; Field 2001: 58; Harnad 1994: 386; Haugeland 1985: 91: 117–123; Pylyshyn 1984: 50).