South by Semantics Workshop

Title: Neo-Pragmatism about Truth

Abstract: Deflationists about truth hold that the function of the truth predicate is to enable us to make certain assertions we could not otherwise make. Pragmatists claim that the utility of negation lies in its role in registering incompatibility. The pragmatist insight about negation has been successfully incorporated into bilateral theories of content, which take the meaning of negation to be inferentially explained in terms of the speech act of rejection. One can implement the deflationist insight in the pragmatist’s theory of content by taking the meaning of the truth predicate to be explained by its inferential relation to assertion. There are two upshots. First, a new diagnosis of the Liar, Revenges and attendant paradoxes: the paradoxes require that truth rules preserve evidence, but they only preserve commitment. Second, one straightforwardly obtains axiomatisations of several supervaluational hierarchies, answering the question of how such theories are to be naturally axiomatised. This is joint work with Luca Incurvati (Amsterdam).

Title: Why Communicative Intentions?

Abstract: Grice argued that we communicate by revealing our intentions to change our addressees’ states of mind. I agree, but I don’t think that Grice did a good job of justifying this view or explaining why we would communicate in this way. The why question is important because if Grice is right, ordinary communication is cognitively costly—a point that has stoked criticisms of Grice and inspired alternative models. Psycholinguistic evidence suggests that ordinary human communication does involve lots of cognitively costly reasoning. We pay these costs, I will argue, because it’s worth it for the massive communicative benefits that we get in return. My explanation of these benefits has two parts, corresponding to the first two components of a communicative intention. First: We form intentions to change others’ states of mind as a crucial step in the practical reasoning by means of which we design communicative acts for our addressees. This design process greatly increases the flexibility and reliability of human communication, and allows us to speak natural languages with far greater expressive power. Second: We reveal these intentions to our addressees because this is an important precondition for treating communication as a cooperative joint activity. When this works, it means that a communicator can rely on their addressee to invest their own cognitive resources to the project of understanding and assessing what they say, thereby dramatically expanding the sphere of communicative goals that it is possible to achieve. 

Title: Unnatural Language Semantics

Abstract: Unnatural language semantics is the study of the meaning of words and expressions in languages that are very unlike natural languages. In this talk, I will present several case studies about how unnatural language semantics can inform us about the structure of natural languages. In particular, I will explain and present several case studies of two methods of explaining semantic universals (shared properties of meaning across the languages of the world): one arguing that such universals arise due to learnability, and another due to optimally trading-off the competing pressures of simplicity and informativeness. The talk will conclude with some discussion about the relative merits of the two explanations as well as other avenues where unnatural language semantics can be helpful.

Title: Competing influences on word meaning in context

Abstract: In this talk, I argue for a notion of word meaning in context that characterizes meaning as both intensional and conceptual. I introduce a framework for specifying local as well as global influences on word meaning in context, together with their interactions. In this framework, sentence meaning is represented through a Situation Description System, a probabilistic model which takes utterance understanding to be the mental process of describing to oneself one or more situations that would account for an observed utterance. I will show analyses of sentences containing various contextualization phenomena.

Title: Question Sensitive Abilities

Abstract: There’s an asymmetry in strength between ability can and its negation can’t. While it’s perfectly acceptable to say “I can φ, but I won’t φ,” it’s unacceptable to assert “I can’t φ, but I will φ.” This suggests that, if you can’t φ, then you won’t φ–in other words, can’t φ entails ¬φ. However, this principle appears incompatible with another seemingly true principle. As Kenny (1975) observed, φing doesn’t always entail an ability to φ–hitting a bullseye by sheer luck doesn’t entail an ability to hit bullseyes. But, φ entails can φ is simply the contrapositive of can’t φ entails ¬φ. We resolve this apparent tension by developing a trivalent semantics where ability can is treated as a quantifier over answers to a salient deliberative question. 

Title: “Understanding” and prediction: Disentangling meaning extraction and predictive processes in humans and AI

Abstract: The interaction between "understanding" and prediction is a central theme both in psycholinguistics and in the AI domain of natural language processing (NLP). Evidence indicates that the human brain engages in predictive processing while extracting the meaning of language in real time, while NLP models use training based on prediction in context to learn strategies of language "understanding". In this talk I will discuss work that tackles key problems in both of these domains by exploring and teasing apart effects of compositional meaning extraction and effects of statistical-associative processes associated with prediction. I will begin with work that diagnoses the linguistic capabilities of NLP models, investigating the extent to which these models exhibit robust compositional meaning processing resembling that of humans, versus shallower heuristic sensitivities associated with predictive processes. I will show that with properly controlled tests, we identify important limitations in the capacities of current NLP models to handle compositional meaning as humans do. However, the models' behaviors do show signs of aligning with statistical sensitivities associated with predictive mechanisms in human real-time processing. Leveraging this knowledge, I will then turn to work that directly models the mechanisms underlying human real-time language comprehension, with a focus on understanding how the robust compositional meaning extraction processes exhibited by humans interact with probabilistic predictive mechanisms. I will show that by combining psycholinguistic theory with targeted use of measures from NLP models, we can strengthen the explanatory power of psycholinguistic models and achieve nuanced accounts of interacting factors underlying a wide range of observed effects in human language comprehension.

Title: Evidence and Conditional Propositions 

Abstract: This paper is about the epistemological upshots of Stalnaker’s Thesis, the thesis that, very roughly, the probability in a conditional proposition A >C given some body of evidence should be equal to the probability of C, conditional on A, given that evidence.  A leading way to deliver Stalnaker’s Thesis assumes a pluralist view of conditional propositions, where for each possible evidential accessibility relation there is a corresponding conditional proposition. I show that, given plausible background assumptions, conditional pluralism and its version of Stalnaker’s Thesis entails the Negation Introspection principle for evidence. I reject this conclusion and so reject the pluralist view of conditionals. In its place I develop a monist information-sensitive view of conditionals. The view is monist because there is just one conditional which yields Stalnaker’s Thesis; the view is information-sensitive, because what conditionals are part of our evidence is fully determined by what factual propositions are part of our evidence. I show that this view is able to validate Stalnaker’s Thesis without the introspection principles.