To see where to go from here, let us quickly recapitulate: The data that we have on polysemy and homonymy representation is limited, but it clearly supports the following claims: (i) Semantic relatedness is a matter of degree, and lexically ambiguous expressions can be placed along a continuum ranging from those that are ambiguous between unrelated interpretations to those that are ambiguous between highly related interpretations. (ii) There is a notable correlation between the degree to which the interpretations associated with a lexically ambiguous expression are judged as semantically related and the degree to which facilitation effects occur in the processing of that expression. Importantly, and as I have argued, the Architectural Explanation fails to explain, and even conflicts with, this data. This being the case, a Non-Architectural Explanation of the processing data ought to be considered. That is, an explanation of why polysemes are processed with more ease than homonyms which does not make reference to the way in which our mental lexicons and their entries are structured. Entertaining such an alternative would, however, be considered controversial. The rise of the Architectural Explanation has been fueled by the now pervasive assumption that differences in ambiguity processing and resolution can only be explained by there being some corresponding differences in the architecture of our mental lexicons. For a Non-Architectural Explanation to be viable, this assumption must be rejected.

Consider the following exchange: Foraker and Murphy (2012) argue that the senses associated with polysemes are represented in separate lexical entries just as the meanings associated with homonyms are. This conclusion is questioned by Brocher and colleagues (2018) on the basis that evidence against that conclusion was already found in Foraker and Murphy’s own post-hoc testing. Foraker and Murphy found overall dominance effects for polysemes consistent with dominance effect patterns that are typical for homonyms. However, their post-hoc testing suggested that the strength of the observed dominance effects could be predicted by the degree to which senses were rated as similar. This should not be seen nor predicted, Brocher and colleagues state, if a separate entries account were correct (2018, p. 445). But why would a separate entries account like Foraker and Murphy’s be incompatible with perceived meaning similarity having effects on processing? The reason seems to be precisely the assumption that differences in ambiguity processing and resolution can only be explained by there being some corresponding differences in the architecture of our mental lexicons. However, this assumption is ill-considered, for a proponent of a separate entries account just needs to make reference to some other factor capable of influencing processing to make sense of this data. A natural contender for such a factor would seem to be the fact that the associated senses are judged as related. Devitt (2021) makes a similar point, criticizing the idea that any separate entries account must predict that polysemes are processed just like homonyms are.Footnote 11

Why predict that the sense dominance that is significant for homonyms would also be significant for polysemes? Though the mind’s path for the efficient processing of homonyms utilizes dominance, perhaps that for polysemes utilizes only those relations. Perhaps the fact that the meanings of a polyseme are related yields much better clues to its interpretation in a context than the crude fact that one meaning is dominant. I see no basis for predicting otherwise. (Devitt 2021, p. 153)

It is not clear why the Architectural Explanation should immediately be favored over an explanation along these lines. In the following, I sketch three alternative ways of explaining why processing differences occur that are neutral with respect to how polysemes are mentally represented in the lexicon.Footnote 12 All three alternatives face some challenges, but the main point is to show that these alternatives exist.

5.1 Option 1: It is due to World Knowledge

The first option is an alternative hinted at by Löhr (2021), and it says that the reason why two meanings are perceived as related is because they denote very similar things. This is something that we know; it is part of our world knowledge that, say, the chair’s arm is similar to the person’s. Löhr writes:

It could simply be argued that the intuition of relatedness stems from the fact that the conventionalized senses of polysemic expressions tend to pick out very similar kinds of things. This intuition of similarity could be represented independently as part of world knowledge. (p. 13)

It is perfectly reasonable to assume that intuitions of similarity, stemming from our knowledge about the things ambiguous expressions can denote, could affect how these ambiguities are processed but not necessarily how they are represented in our mental lexicons. The core idea would be that an ambiguous expression is considered polysemous when the things denoted by its various senses are perceived as similar, and that this intuition of similarity is what influences the disambiguation process. We can summarize the suggested view of polysemy as follows:

KNOWLEDGE

An expression E is polysemous between two meanings, M1 and M2, for a subject S, if and only if (i) S regularlyFootnote 13 associates E with M1 and M2, (ii) M1 and M2 are distinct, and (iii) S perceives the things denoted by M1 and M2 as similar.Footnote 14

We can generate different versions of this alternative by explicating what “perceives as similar” really means.

While an option like this is worth exploring, it has several problems. An analysis along these lines assumes that for a subject to perceive two interpretations of an ambiguous expression as semantically related, she must perceive the things denoted as similar. However, it is doubtful that this is always the case. For example, I might regard the use of ‘mouth’ to pick out apertures as related to the use of ‘mouth’ to pick out parts of rivers where they meet the sea, but I need not think that apertures and parts of rivers are similar things at all. As a result, the proposal will seemingly fail to account for cases in which the things denoted by an ambiguous expression are not perceived as similar, but where the senses associated with that expression are still judged as related and effects on processing are present. Alternatively, the proposal risks attributing intuitions of similarity to speakers that they do not have.

Consider further the use of ‘suit’ to denote, on the one hand, a type of clothing and, on the other, executives. These two alternative meanings are clearly related, but are they so related because executives are similar to suits? It seems more plausible to think that the reason we perceive these two meanings as related is because of the fact that we only began calling executives ‘suits’ because suits are what executives wear. This brings us to the second option I want to consider.

5.2 Option 2: It is due to Causal Relations

The second option is Devitt’s (2021). On this alternative, judgments of relatedness are due to causal relations between associated meanings. All senses associated with a polyseme, Devitt argues, are causally related, for “the polyseme came to have its related senses because its having one sense partly caused it to have others; ‘suit’ came to mean an executive because it meant what an executive wears” (2021, p. 148). From the start, they were related via an “association of ideas,” something which we might expect to affect processing, but not necessarily representation, Devitt goes on to argue. We can spell out this alternative characterization of polysemy as follows:

CAUSAL RELATIONS

An expression E is polysemous between two meanings, M1 and M2, for a subject S, if and only if (i) S regularly associates E with M1 and M2, (ii) M1 and M2 are distinct, and (iii) the use of E to express M1 in S’s linguistic community is causally related to S’s linguistic community’s use of E to express M2.Footnote 15

This option does away with the requirement that subjects must perceive the things denoted by the two meanings as similar but faces other problems. Firstly, this solution presupposes that we all have access to these causal facts, for how else could they influence our processing? However, it can be doubted that ordinary speakers generally have access to such facts. Furthermore, the solution entails that for an expression to be polysemous for some individual, the interpretations associated with that expression must in fact be causally related. Let us look at a hypothetical scenario sketched by Carston (2021) in order to see why this is problematic. Carston says:

Suppose, for instance, that a form /xyz/ denotes the beak of a certain breed of bird and also a particular kind of bracket used in assembling furniture, there being no historical connection between the two words, but it happens that the bracket has a beak-like shape and movement. (p. 110)

The question is, is this a case of homonymy or polysemy? The most reasonable answer to this question is the one that Carston gives, namely, that it will depend on the speaker (cf. Löhr 2021). ‘Xyz’ will be polysemous for an individual who perceives the two meanings as related, whereas ‘xyz’ will be homonymous for an individual who does not. The scenario is interesting to consider, as there are real-life examples of precisely the type of situation Carston describes. That is, cases in which an expression is polysemous for some speakers but homonymous for others. Consider this passage from Murphy (2010):

I assumed for years that the word ear was a polyseme that could mean ‘an organ for hearing’ or ‘a cob (of corn).’ It seemed to me that cobs of corn came to be called ears (in North America at least) because they stick out from the stalk the same way that our ears stick out from our heads. But later I found out that (a) many people do not see a similarity between the two senses, and (b) the words for hearing organs and corncobs are not etymologically related. […] On etymological grounds and in other people’s minds, ear is a homonym.Footnote 16 (pp. 91–92)

No study, as far as I am aware, has experimented on expressions with associated meanings that are clearly related in the minds of some individuals, but unrelated in the minds of others. However, we should expect that, given an ambiguous expression E, those individuals who believe that the meanings associated with E are related will process E differently compared to those who do not think that they are. This should be expected, given what we know about how the degree to which meanings are judged as related correlates with effects on processing.

These kinds of examples pose a problem for Devitt precisely because he assumes that what distinguishes polysemy from homonymy, and explains differences in processing, is that the meanings associated with a polyseme are causally related. Hence, ambiguous expressions whose associated meanings are not causally related cannot be polysemous, even if everyone believes that their meanings are related.

If we read Devitt as saying that these causal relations are, instead, in the minds of individual speakers, Devitt’s solution is committed to the view that for two meanings, M1 and M2, to be related in the mind of a subject S, S’s having M1 must have partially caused S’s having M2 (or vice versa). Furthermore, these causal relations must still be in S’s mind somehow affecting S’s processing. But now, just because I regard the use of ‘mouth’ to pick out oral cavities as related to the use of ‘mouth’ to pick out parts of rivers where they meet the sea, why must my having the one sense of ‘mouth’ have been caused by my having the other? Maybe my having the second sense was caused simply by people telling me that ‘mouth’ means parts of rivers where they meet the sea. I can still regard the two senses as related, for I can come to believe that the reason why these parts of rivers are called ‘mouths’ is because someone once thought they were interestingly similar to our oral cavities in some respect, just as Murphy believed that cobs of corn came to be called ‘ears’ because the way they stick out from the stalk is similar to the way that our ears stick out from our heads. But then, it is my belief that the senses are so related which relates them.

5.3 Option 3: It is due to Metalinguistic Beliefs About Causal Relations

Given what was said in the previous section, a third option presents itself. According to this alternative, when an expression E is associated with two different interpretations and a subject S believes them to be causally related, this will affect how S processes occurrences of E. It could be the case that S is unaware that two interpretations associated with an expression E1 are causally related and thus processes E1 like a mere homonym. It might also be the case that S wrongly believes that two causally unrelated interpretations associated with some expression E2 are related, which will lead S to process E2 differently than E1. Importantly, it is perfectly reasonable to suppose that our metalinguistic beliefs are capable of affecting processing but not necessarily representation. In sum, the proposal is as follows.

BELIEFS

An expression E is polysemous between two meanings, M1 and M2, for a subject S, if and only if (i) S regularly associates E with M1 and M2, (ii) M1 and M2 are distinct, and (iii) S believes that the use of E to express M1 in S’s linguistic community is causally related to S’s linguistic community’s use of E to express M2.Footnote 17

This option avoids the problems associated with Option 1 and Option 2. It does, however, raise an immediate question: How does Murphy process occurrences of ‘ear’ now when she has learned that the two alternative meanings are unrelated and supposedly no longer believes them to be? This is an empirical question that would require investigation, but if the same facilitation effects still occur, that is a problem for Option 3. To mend it, one might propose a view that combines Option 1 and Option 3. Because, maybe, people like Murphy who have believed that the two meanings associated with ‘ear’ were causally connected for so long have come to perceive the ears of corn and the ears of humans as similar, and that is something which might be hard to, so to speak, unsee. This would yield a characterization of polysemy along the following lines:

KNOWLEDGE AND BELIEFS

An expression E is polysemous between two meanings, M1 and M2, for a subject S, if and only if (i) S regularly associates E with M1 and M2, (ii) M1 and M2 are distinct, and (iii) S believes that the use of E to express M1 in S’s linguistic community is causally related to S’s linguistic community’s use of E to express M2 or S perceives the things denoted by M1 and M2 as similar.

According to this alternative, what influences our judgments of relatedness and the way we process ambiguous expressions is our knowledge and our beliefs about the things ambiguous expressions can denote, as well as our beliefs about how meanings are related. This alternative keeps what was good about Option 1 but can also account for judgments of relatedness that stem from our beliefs about meaning relations. Thus, it is worthy of further attention in the literature.

5.4 The Continuum Puzzle Revisited

While these Non-Architectural Explanations avoid the original version of the continuum puzzle, one might worry whether the continuum puzzle does not arise again but in another form.Footnote 18 How do the alternatives proposed here explain why processing is facilitated in varying degrees?

Option 1 can provide a rather simplistic answer: The more similar the things denoted by the two alternative meanings are perceived to be, the more prominent the facilitation effects will be. Option 2 has a harder time accounting for the continuum. However, we might imagine that a solution would be to say that the closer the causal relation between two senses is, the more prominent the facilitation effects will be. Thus, no facilitation effects will occur if two senses are very distantly related. A proponent of Option 2 would then have to spell out what she means by two senses being “distantly related,” for this could be interpreted in different ways. Cashing it out in terms of the number of intervening steps would only work for a handful of cases, so she will probably want to say that two senses are distantly related when the ambiguity was established so long ago that speakers of the language have started to forget what the relevant association of ideas really was about.Footnote 19 The challenge is perhaps most acute when it comes to Option 3. In what manner can our metalinguistic beliefs account for when and why facilitation effects occur to varying degrees? Perhaps one can appeal to how strongly held the belief is, e.g., our credences toward the proposition that M1 and M2 are related. That is possible, but the resulting picture would perhaps provide a too intellectualized account of the issue. It can be objected that people simply do not have sophisticated metalinguistic beliefs of that kind. The issue is not one that I will be able to resolve here, but it merits further discussion. What I will say is this: investigating and discussing this particular issue puts us in a better position to understand why polysemes are processed with more ease than homonyms.