7.8—
The Interpretability-in-principle Version
There is, however, a fourth modality under which marker tokens can be said to be signifiers: namely, interpretability-in-principle. The Interpretability-in-Principle Version of CTM explained the semantic and intentional properties of an organism O 's cognitive state A —say, its meaning (that) P —by positing a mental representation MP and a functional relation R such that (1) MP is interpretable-in-principle as meaning (that) P , and (2) O is in relation R to MP . Two coextensive definitions for semantic interpretability-in-principle were offered in chapter 4. One definition was framed in terms of counterfactuals about conventions, the other in terms of the availability of a mapping from marker types to interpretations. Since the former definition seems clearly to risk running afoul of the same problems about convention that have already been discussed, we may assume that the second definition holds more promise for CTM. This definition was formulated as follows:
(S4* ): An object X may be said to be interpretable-in-principle as signifying Y iff
(1) X is interpretable-in-principle as a token of some marker type T ,
(2) there is a mapping M from a set of marker types including T to a set of interpretations including Y , and
(3) M(T) = Y .
Now semantic interpretability-in-principle is a very permissive notion. Every object is interpretable-in-principle as a token of a marker type (i.e., can, in principle, be used as a marker if someone comes up with a suitable marker convention); and every marker type can be mapped onto whatever interpretation one likes. Therefore, for every object X and every interpretation P , X is interpretable-in-principle as meaning (that) P .
One thing that should be noted about the notion of interpretability-in-principle is that the connection it makes between marker types and interpretations is not dependent either upon actually existing semantic conventions or upon acts of authoring or interpretation. And this has the significant consequence that the Interpretability-in-Principle Version of Fodor's account of cognitive states is immune to the criticisms raised against the Interpretability, Authoring Intention, and Actual Interpretation Versions. To put it differently, the logical form of attributions of semantic interpretability-in-principle does not involve references to semantic conventions or meaning-bestowing acts, with the consequence that the preceding arguments do not show that the Interpretability-in-Principle Version suffers from the pernicious kind of conceptual dependence that threatened the other versions.
I shall argue, however, that the Interpretability-in-Principle Version is also incapable of supplying a viable account of the semantic and intentional properties of cognitive states. In particular, there are four distinct problems. First, such an account would impute to mental states semantic and intentional properties which they clearly do not have. Second, it would impute the kinds of semantic and intentional properties that we ascribe to mental states to objects that clearly do not have them. Third, it would not provide an explanation of the intentionality and "semanticity" of mental states. And, finally, the definition of being interpretable-in-principle as a signifier token presupposes being interpretable-in-principle as a marker token—and that does involve conventions in a way that leads to circularity and regress, albeit not at the semantic level.
7.8.1—
Spurious Properties
The first problem with the Interpretability-in-Principle Version is that it would impute to mental states intentional and semantic properties that they clearly do not have. According to the Interpretability-in-Principle Version, for example, an organism O can have a belief about Lincoln just in case (1) O is in the right functional relationship R to a mental representation MP , and (2) MP is interpretable-in-principle as being about
Lincoln. Now if there are mental representations, it is surely the case that any mental representation MP is interpretable-in-principle as being about Lincoln—the definition of interpretability-in-principle is so permissive as to assure that. But by the same token, the definition is also so broad as to assure that MP is interpretable-in-principle as being about the number two, the Crimean War, or anything else. Indeed, for every interpretation P, MP is interpretable-in-principle as being about P .
Now suppose that (as the Interpretability-in-Principle Version suggests) O 's being in relation R to MP , in conjunction with MP 's being interpretable-in-principle as being about P , are conditions jointly sufficient for ascribing to O a belief about P . If this is the case, then O has beliefs about everything, since each marker token MP is interpretable-in-principle as being about everything. Indeed, each of O 's beliefs is about everything, since each belief involves a marker token that is interpretable-in-principle as being about everything.
Surely this consequence of the Interpretability-in-Principle Version is intolerable. There may sometimes be some unclarity, vagueness, and ambiguity as to just what our beliefs are about, but not to the extent that each of our beliefs is about everything! And as this is a consequence of the Interpretability-in-Principle Version, so much the worse for that account.
7.8.2—
Strange Cognizers
Depending upon how one takes the words 'organism' and 'functional relation' in Fodor's characterization of cognitive states, there may be a second problem for this version of the account as well. For one might well think that Fodor does not really mean to restrict his characterization of cognitive states to organisms . To do so in the context of a computational theory of mind would be very odd indeed! Perhaps the word 'system' could usefully replace the word 'organism'. And one might well think that the word 'functional' is used in the sense that it is used when one classifies digital machines according to their machine tables—that is, according to functional relationships between current states and succeeding states.
But if one does interpret Fodor in this way, it would seem that all kinds of things turn out to be cognizers. For, according to Fodor's account, it would seem that if (a ) two systems are functionally equivalent, and (b ) their symbols have the same semantic and intentional properties, and (c ) they are in equivalent functional relations to their symbols, then it should
be the case that they are in the same cognitive states. But consider the following problem. If a cognizer is describable in purely formal terms, it must be the case that there is an abstract formal system that is functionally equivalent to the cognizer. And if interpretability-in-principle is all that is needed to give a symbol system the kind of intentional and semantic properties that mental states enjoy, then it would seem to be the case that abstract symbol systems have intentional and semantic properties in just the same senses that mental states do. Presumably this would be enough to include such systems in the class of cognizers. But surely such a conclusion would be absurd.
7.8.3—
Lack of Explanatory Force
Even if we could avoid these problems, it is difficult to see how the interpretability-in-principle of a marker token could supply anything in the way of an explanation of the meaningfulness or intentionality of a mental state. Suppose that I wish to know why a particular state of Jones's is about Lincoln and someone tells me that it is because Jones is in a particular functional relationship to a mental representation, and that representation is about Lincoln. I then ask, "Why is that mental representation about Lincoln?" If the reply is merely, "Because there is a mapping from that representation's marker type to Lincoln," then I have not received an explanation. Even if I believe everything that I have been told, I still don't know why Jones's cognitive state is about Lincoln. Pointing to the availability of a mapping just does not supply the kind of information that would answer my question. (It is not clear just what would supply the right kind of information, but it is clear that this reply does not.)
7.8.4—
The Reappearance of Conventionality at the Marker Level
Finally, upon closer inspection, it turns out that the notion of semantic interpretability-in-principle is not so free of convention as at first it seemed. The connection between marker types and interpretations is, indeed, not conventional. But for an object to be interpretable-in-principle as a signifier, it must first be interpretable-in-principle as a marker, and the expression 'interpretable-in-principle as a marker' does have a conventional aspect. For remember how this notion was defined:
(M4): An object X is said to be interpretable-in-principle as a token of a marker type T iff
(1) a linguistic community could, in principle, employ conventions governing a marker type T such that any object having any pattern PiÎ P :{P 1, . . . , Pn } would be suitable to count as a token of type T ,
(2) X has a pattern p j, and
(3) pjÎP .
An object's being interpretable-in-principle as a marker is not just a matter of there being a mapping from one object to another, because marker types are necessarily conventional. The very notion of a marker is convention-dependent.
This has the consequence that the Interpretability-in-Principle Version does involve conceptual dependence upon cognitive notions. For while attributions of semantic interpretability-in-principle do not involve tacit ascriptions of semantic conventions or intentions, they do involve tacit reference to marker conventions. Any explanation of marker conventions, like semantic conventions, would have to involve reference to a community of symbol users who share a certain understanding about marker types and tokening. And this shared understanding must surely consist in large measure in the members of the community being in relevantly similar mental states. But if this is so, the Interpretability-in-Principle Version is bound to end in the same kind of circularity and regress as the other versions.