7.4—
The Empirical Implausibility of the Account

The first problem with the versions of CTM based on convention and intention is that they are highly implausible as empirical theories. Indeed, they are so empirically implausible that it would be difficult to find any stranger theories in the history of science. For suppose that the semiotic-semantic version of CTM is true. If this is so, then whenever you have a belief that (for example) Lincoln was president, you have a mental representation MP that means (that) Lincoln was president. And if one of

the three versions of CTM based on conventions or intentions is correct, 'means (that)' has to be cashed out in terms of conventions or intentions. According to the Interpretability Version, you can only have a belief that Lincoln was president if there is some convention C that licenses the interpretation of MP as meaning that Lincoln was president. According to the Authoring Intention Version, you can only have such a belief if someone "authored" MP and intended it to mean that Lincoln was president. And according to the Actual Interpretation Version, you can only have such a belief if someone apprehends MP and takes it to mean that Lincoln was president.

All of these possibilities seem very unlikely, to say the least! Who is it , after all, whose intentions, interpretations and conventions are supposed to explain the meaningfulness of MP? One possibility would be that it is the thinker's own intentions, interpretations, or conventions. But there are two problems here, both of which may be familiar from criticisms of Hume offered by Thomas Reid and Edmund Husserl. First, there is certainly no experience of authoring or interpreting a symbol in ordinary cognition. (And it is not clear what it would mean to interpret or author a symbol one does not and cannot apprehend.) Second, in order to intend or interpret a symbol token as being about something else, one must have access both to the symbol and to the thing it is to represent. As we shall see below, this runs afoul of some basic motivations for representational theories of mind.

But perhaps the relevant conventions and intentions are not those of the organism itself, but of some other being(s). It is, perhaps, conceivable that there are some supernatural beings, or perhaps some very sophisticated Martian psychologists, who have subtle enough access to human brain states to view them as computers—for example, by constructing Turing machine descriptions for each human being. But it really seems quite unlikely. And according to these convention- and intention-based versions of CTM, humans could only be said to be in cognitive states if there were such beings. A theory that appeals to the unlikely to explain the matter-of-fact surely has to be regarded as highly suspect.