Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - EXPRESS (From the Expression of Disagreeement to New Foundations for Expressivist Semantics)

Teaser

Disagreement is a pervasive feature of human life. Democrats and Republicans disagree over whom the next US President should be. Public opinion is divided over which measures to take in the face of climate change. Citizens of the United Kingdom disagree over whether leaving...

Summary

Disagreement is a pervasive feature of human life. Democrats and Republicans disagree over whom the next US President should be. Public opinion is divided over which measures to take in the face of climate change. Citizens of the United Kingdom disagree over whether leaving the EU will negatively impact their nation’s economy.

Disagreement finds linguistic expression in the speech-act of rejection (also called denial). Suppose you say that Amsterdam is in Belgium. In so doing, you perform an assertion—a speech-act in which something is claimed to be the case. I can express my dissent with you by responding ‘no’, thereby rejecting your assertion.

In the study of human language, the speech-act of assertion has taken centre stage. Philosophers have formulated several competing accounts of assertion. Linguists have constructed detailed models of the conversational effects of assertion. Logicians have investigated the mathematical properties of systems involving assertions.

By contrast, the speech-act of rejection has been largely neglected, and its investigation has traditionally been regarded as a chapter in the study of assertion. The EXPRESS project aims to articulate a full-fledged theory of rejection which is philosophically and linguistically sound. The importance of this endeavour cannot be overestimated: without such a theory of rejection, we cannot properly understand the way disagreement is expressed and our understanding of the mechanisms of conversation—in which rejection plays a central role—is severely limited.

Once the importance of rejection is appreciated, it becomes pressing to understand what its logic is, in the same way as much effort has been put into studying the logic of assertion. The project therefore aims to develop a logic of rejection faithful to the linguistic phenomena. We also aim to implement the logic in a computational model for detecting agreement or disagreement in dialogue. Potential applications include the development of tools to be used in online education discussion boards to help educators determine the extent of agreement and disagreement on specific topics within a study group.

The theory and logical framework developed will be used to establish a novel approach to natural language semantics, inferential expressivism. This approach will lead to distinctive hypotheses about language evolution which will be studied using computational modelling techniques.

Work performed

The research team was set up, and consists of the PI (Luca Incurvati), a postdoc in Language and Computation (Giorgio Sbardolini), a postdoc in Logic (Julian Schlöder), a PhD student in Philosophy of Language and Semantics (Leïla Bussière) and a research assistant (Patty den Enting).

Substantial progress on the project’s goals has been made. We have worked on the development of a full-fledged theory of rejection, expanding and modifying extant models of conversation to take into account the fact that speakers not only assert or accept what is being asserted but often reject.

Paying close attention to the linguistic phenomena, we have identified and studied weak and strong forms of assertion and rejection. We have then used these weak and strong forms of assertion and rejection to develop what we call a ‘multilateral logic framework’, a logical framework which has the resources to handle not only assertion (like standard logical systems) but also other speech acts. The mathematical properties of this framework have been extensively studied.

We have applied the approach to natural language semantics advanced in the project, inferential expressivism, to a variety of areas and linguistic expressions, including natural language negation, epistemic modals (e.g. expressions such as `might’ in `Elizabeth Warren might win the Democratic primaries’) and moral vocabulary (e.g. expressions such as `wrong’).

In the context of language evolution, we have begun using computational techniques to study the importance of rejection, the emergence of negation (whose presence is effectively universal in human languages) and the emergence of epistemic modality.

Other themes team members have worked on include the nature of propositions, disagreement in logic (with particular attention to the role of logic in disputes over non-logical matters) and the use of counterfactuals (sentences such as ‘If kangaroos had no tails, they would topple over’) to understand what it means for something to be knowable.

The interplay between philosophical and linguistic analysis, logical methods and computational techniques has proved particularly fruitful. The work pursued in the project has appeared in top logic and philosophy journals and a number of events associated with the project have been organized, namely a weekly reading group, a seminar with invited speakers and a three-day international workshop.

Final results

We plan to continue the study of rejection and the development of the multilateral framework. Important areas to which we aim to apply the multilateral framework include the interplay between quantification and epistemic modality, formal theories of truth and probability theory. This will allow us to extend the approach to natural language semantics advanced in the project, inferential expressivism, to a large variety of linguistic expressions whose analysis is notoriously difficult. Our aim by the end of the project is to have provided the foundations for a novel approach to natural language semantics which is philosophically motivated, linguistically and logically grounded, and improves on extant approaches in the way it deals with several logical and linguistic problems.

The use of computational techniques to study language evolution will be continued. We expect to construct models and obtain data using computer simulations to provide evidence that the presence of rejection facilitates the emergence of negation and communication. Further investigations to be carried out using computational methods concern the implementation of the multilateral framework to develop tools for the automatic detection of agreement and disagreement in dialogue.

Website & more info

More info: https://inferentialexpressivism.com.