5.1.1—
The Homonymy of the Semantic Vocabulary

The case for homonymy is fairly straightforward. First, if a natural language verb V is used in two contexts, A and B , and the logical form of V -assertions in A differs from that in B , then V is used to express different predicates in the two contexts. Moreover, predicates with different logical forms express different properties . In particular, two predicates expressing relational properties can only express the same property if they relate the same number of relata. Predicates with different numbers of argument slots in their logical form relate different numbers of

relata, and hence express different properties.^[1] Likewise, two predicates with the same number of arguments do not express the same property if the things that can fill their argument slots come from different domains.

Second, the predicates used to express semantic properties of symbols have argument slots that must be filled by references to conventions and intentional agents . They thus express complex relational properties that essentially involve conventions and agents. This much is a straightforward consequence of the Semiotic Analysis. One may contest the analysis on other grounds; but if one accepts it, one has already bought into this consequence.

Third, the logical forms of attributions of semantic properties to minds and mental states do not contain argument slots to be filled by references to conventions or intentions, and hence they attribute properties distinct from the semiotic properties . I have always thought that this was pretty self-evident, but sometimes people have accused me of just asserting this point without arguing it. The only way I see to demonstrate this point is to test each of the schemas developed in chapter 4 as a possible interpretation of attributions of semantic properties to mental states and see whether any of them seem intuitively plausible. So suppose John is having a thought T at time t , and what he is thinking about is Mary . We say (in ordinary English)

"John is thinking about Mary,"

or (in awkward philosophical jargon)

"John's thought T is about Mary."^[2]

Now can this be analyzed in terms of conventional interpretability in a language? That is, could the logical form of this utterance possibly be the following?

(1) John's thought T is interpretable under convention C of language L as being about Mary.

The answer, I think, is clearly no . The more you think about "meanings" of utterances, the clearer it becomes that there is a notion of conventional meaning in a language that applies there, and that it is part of what we meant all along when we spoke of meaning for symbols. But it is hard to see how that notion could apply to thoughts . Except for special cases like the interpretation of dreams, there are no conventions for interpretating thoughts. Nor do thoughts require such conventions for interpretation: thoughts come with their meanings already attached. You can-

not separate the thought from its meaning the way you can separate the marker from its meaning. This is why some writers describe the semantics of mental states as intrinsic to them.

Likewise for the other semiotic modalities:

(2) John intended that this thought T be about Mary.

(3) H apprehended John's thought T and interpreted it as being about Mary.

We do sometimes have thoughts as a result of intentions to have thoughts, as suggested in (2). John might, for example, deliberately think about his wife Mary while he is away on a business trip on their anniversary. Or, dealing with transference on a therapist's couch, he may intend to think about Mary but end up thinking about someone else instead. These things happen, but they are surely not what we are talking about when we say John's thought T is about Mary. Usually the intentionality of our thoughts is unintentional.

As for (3), there is some question about whether we apprehend one another's thoughts at all. We surely guess at one another's thoughts, and may rightly or wrongly surmise that John's thought at a given time is about Mary. But this is very different from seeing a marker as a marker and then interpreting it. We never apprehend thoughts as markers. And more to the point, even if we do apprehend people's thoughts and interpret them, this is not what we mean when we attribute meaning to their thoughts. I might say of a symbol, "It means X to Jim ." But it surely makes no sense to say, "John's thought means 'Mary' to Jim " (or for that matter, "John's thought means 'Mary' to John"). Finally, when we say that John's thoughts are about Mary, we certainly do not mean merely to assert the existence of a mapping relationship (i.e., interpretability-in-principle) from John's thought to Mary. If we try to apply the logical form of the semiotic vocabulary to our attributions of meaning to mental states, the results are nonsensical.

So semantic terms like 'means' and 'is about' have a different logical form when applied to mental states. It does seem reasonable to construe the logical form of these attributions as involving a three-place predicate relating subject, thought-token, and meaning, as the surface grammar suggests. There are no hidden references to conventions and intentions. As a consequence, the semantic vocabulary also expresses distinct properties when applied to mental states. When applied to symbols, it expresses relational properties in which some of the relata are conventions

or producers and interpreters of symbols. But these relata are missing in the case of mental states. In short, differences in logical form point to differences in properties expressed.

It thus behooves us to differentiate between two classes of properties that are expressed using the same semantic vocabulary: there is one set of semiotic-semantic properties as described by the Semiotic Analysis in chapter 4, and a separate set of mental-semantic properties attributed to mental states.