M. Stone

We think it best to keep our observations general and minimal. The essays in this volume are clear and well argued, but we feel the same about our own book, and so, it would be otiose to dive deeper into the dialectic. Instead we will discuss a few areas where we believe additional research is needed to adjudicate central issues concerning the rules of language and the processes of interpretation which we take to be open, focusing primarily on conventions, intentions and coherence relations. We end with some comments on the scope of meaning in language and its consequences for the semantic enterprise.

Our goal in this chapter is to contest the traditional view of indirection in utterances such as, ‘Can you pass the salt?’ by developing a very different way of characterizing the interpretations involved. We argue that the felt “indirection” of such utterances reflects the kind of meaning the utterances have, rather than the way that meaning is derived. So understood, there is no presumption that indirect meanings involve the pragmatic derivation of enriched contents froma literal interpretation; rather, we argue that indirect meanings are explicitly encoded in grammar. We build on recent work on formalizing declarative, interrogative, and imperative meanings as distinct but compatible kinds of content for utterances.

The view put forward in this chapter about slur terms is that their interpretations require expansive, open-ended engagement with an utterance and its linguistic meaning, through a host of distinctive kinds of reasoning. This reasoning may include inferences about the speaker’s psychology and her intentions—in light of the full social and historical context—but it may involve approaching the utterance through strategies for imaginative elaboration and emotional attunement, as required, for example, for metaphor, poetic diction, irony, sarcasm, and humor. In the face of their heterogeneity and open-endedness, these interpretive strategies are most perspicuously elucidated through critical attention to the psychological, social, historical, and even artistic considerations at play in specific cases. Thus, in contrast to the common practice in philosophy and linguistics, this chapter will not offer a general account of the interpretation of slur terms. It puts forward that there can be no such thing.

What is the will? And what is its relation to human action? Throughout history, philosophers have been fascinated by the idea of 'the will': the source of the drive that motivates human beings to act. However, there has never been a clear consensus as to what the will is and how it relates to human action. Some philosophers have taken the will to be based firmly in reason and rational choice, and some have seen it as purely self-determined. Others have replaced the idea of the human will with a more general drive uniting humans and the rest of nature, living and non-living. This collection of nine specially commissioned papers trace the formulation and treatment of the problem of the will from ancient philosophy through the scholastic theologians of the Middle Ages, to modern philosophy, and right up to contemporary theories. Philosophers discussed include Plato, Aristotle, Augustine, Aquinas, Bonaventure, Hobbes, Kant, Schopenhauer and Nietzsche.

Nonprofit organizations operate in environments characterized by institutional demands for legitimacy and by centralized but often fragmented funding sources. They must satisfy the often conflicting demands of multiple stakeholders -- among them funders, community and user groups, and professional associations -- in order to gain access to critical resources. This paper argues that, given this environment, strategy for nonprofits is better framed in terms of corporate political strategy than competitive strategy.

Joint inquiry requires agents to exchange public content about some target domain, which in turn requires them to track which content a linguistic form contributes to a conversation. But, often, the inquiry delivers a necessary truth. For example, if we are inquiring whether a particular bird, Tweety, is a woodpecker, and discover that it is, then our inquiry concluding in this fact would conclude in a necessity, and the form “Tweety is a woodpecker” expresses this necessary truth. Still, whether Tweety is a woodpecker seems a perfectly legitimate object of study, and the answers we accrue can be informative. But the dominant model of inquiry (Stalnaker, 1978, 1984) treats this situation as linguistically deviant, and diagnoses our ignorance and subsequent discovery as metalinguistic: we were ignorant, and ultimately discovered something, about the meaning of our terms. Rather than linguistic deviation, we argue this situation is the norm, and one that calls for an alternative model of inquiry. This paper develops such a model. It shows that to capture how agents can learn something informative about the world—and not merely language—even when inquiry concerns necessary facts, it's key to track how moves in discourse contribute public content onto the conversational record, but also, crucially, how those moves are connected by coherence relations to one another and to real‐world situations they are about. This allows us to capture that utterances contribute determinate, public content, while representing the information states of the interlocutors who may have only partial access to the evidence and content of the conversation, without making their ignorance metalinguistic. It lets us give precise explanations why some discourses can be transparently convincing in the conclusions they underwrite. The model thus precisifies the role of public context and shared content in anchoring an inquiry. It allows for imperfect tracking of linguistic contributions that are binding for how inquiry unfolds, and it allows for an inquiry into the status of necessary truths to be both informative, and involve empirical, rather than metalinguistic, ignorance.

What is the will? And what is its relation to human action? Throughout history, philosophers have been fascinated by the idea of 'the will': the source of the drive that motivates human beings to act. However, there has never been a clear consensus as to what the will is and how it relates to human action. Some philosophers have taken the will to be based firmly in reason and rational choice, and some have seen it as purely self-determined. Others have replaced the idea of the human will with a more general drive uniting humans and the rest of nature, living and non-living. This collection of nine specially commissioned papers trace the formulation and treatment of the problem of the will from ancient philosophy through the scholastic theologians of the Middle Ages, to modern philosophy, and right up to contemporary theories. Philosophers discussed include Plato, Aristotle, Augustine, Aquinas, Bonaventure, Hobbes, Kant, Schopenhauer and Nietzsche.

The commonplace view about metaphorical interpretation is that it can be characterized in traditional semantic and pragmatic terms, thereby assimilating metaphor to other familiar uses of language. We will reject this view, and propose in its place the view that, though metaphors can issue in distinctive cognitive and discourse effects, they do so without issuing in metaphorical meaning and truth, and so, without metaphorical communication. Our inspiration derives from Donald Davidson’s critical arguments against metaphorical meaning and Richard Rorty’s exploration of the diverse uses of language. But unlike these authors we ground our discussion squarely in distinctions about causal mechanisms in cooperative activity developed by H.P. Grice and others.

We use a dynamic, context-sensitive approach to abductive interpretation to describe coordinated processes of understanding, generation and accommodation in dialogue. The agent updates the dialogue uniformly for its own and its interlocutors’ utterances, by accommodating a new context, inferred abductively, in which utterance content is both true and prominent. The generator plans natural and comprehensible utterances by exploiting the same abductive preferences used in understanding. We illustrate our approach by formalizing and implementing some interactions between information structure and the form of referring expressions.

This paper develops a general approach to contextual reasoning in natural language processing. Drawing on the view of natural language interpretation as abduction (Hobbs et al., 1993), we propose that interpretation provides an explanation of how an utterance creates a new discourse context in which its interpreted content is both true and promi- nent. Our framework uses dynamic theories of semantics and pragmatics, formal theories of context, and models of attentional state. We describe and illustrate a Prolog implementation.

In abductive planning, plans are constructed as reasons for an agent to act: plans are demonstrations in logical theory of action that a goal will result assuming that given actions occur successfully. This paper shows how to construct plans abductively for an agent that can sense the world to augment its partial information. We use a formalism that explicitly refers not only to time but also to the information on which the agent deliberates. Goals are reformulated to represent the successive stages of deliberation and action the agent follows in carrying out a course of action, while constraints on assumed actions ensure that an agent at each step performs a specific action selected for its known effects. The result is a simple formalism that can directly inform extensions to implemented planners.

We give an overview of the arguments of our book Imagination and Convention, and explain how ideas from the book continue to inform our ongoing work. One theme is the challenge of fully accounting for the linguistic rules that guide interpretation. By attending to principles of discourse coherence and the many aspects of meaning that are linguistically encoded but are not truth conditional in nature, we get a much more constrained picture of context sensitivity in language than philosophers have typically assumed. Another theme is the heterogeneous nature of interpretive processes, as illustrated by the distinctive interpretive profile of metaphorical and poetic language. Such effects remind us that the suggestions and connotations of an utterance are often best explained in terms of the hearer’s experiential engagement with language, without appeal to propositional content that the speaker somehow signals either semantically or pragmatically.

The meanings of donkey sentences cannot be captured using a procedure which, like Montague’s, uses the existential quantifiers of classical logic to translate indefinites and the variables to translate pronouns. The treatment of these examples requires meanings which depend on the context in which sentences appear, and thus necessitates a logic which models this context to some extent. If context is represented as the information conveyed in discourse, and the meanings of pronouns are enriched to depend on this information, the result is the E-Type approach (ETA) adapted by Heim (1990) from proposals in Evans (1980) and Cooper (1979). If the context is represented as a list of potential referents, and the meanings of indefinites are enriched to introduce new referents into this list, the result is a compositional formulation like Groenendijk and Stokhof’s (1990) of the discourse representation theory (DRT) of Kamp (1981) and Heim (1982). Either tack suffices to capture the way in which the referents of he and it systematically correspond to the alternative possibilities described by the antecedent. Disjunction offers a parallel way of introducing alternatives in the antecedent of a conditional, as shown in (2).

In modal subordination, a modal sentence is interpreted relative to a hypothetical scenario introduced in an earlier sentence. In this paper, I argue that this phenomenon reflects the fact that the interpretation of modals is an ANAPHORIC process. Modal morphemes introduce sets of possible worlds, representing alternative hypothetical scenarios, as entities into the discourse model. Their interpretation depends on evoking sets of worlds recording described and reference scenarios, and relating such sets to one another using familiar notions of restricted, preferential quantification. This proposal relies on an extended model of environments in dynamic semantics to keep track of associations between possible worlds and ordinary individuals; it assumes that modal meanings and other lexical meanings encapsulate quantification over possible worlds. These two innovations are required in order for modals to refer to sets of possible worlds directly as static objects in place of the inherently dynamic objects—quite different from the referents of pronouns and tenses—used in previous accounts. The simpler proposal that results offers better empirical coverage and suggests a new parallel between modal and temporal interpretation.

We present an algorithm for simultaneously constructing both the syntax and semantics of a sentence using a Lexicalized Tree Adjoining Grammar (LTAG). This approach captures naturally and elegantly the interaction between pragmatic and syntactic constraints on descriptions in a sentence, and the inferential interactions between multiple descriptions in a sentence. At the same time, it exploits linguistically motivated, declarative specifications of the discourse functions of syntactic constructions to make contextually appropriate syntactic choices.

In this paper, we introduce a system, Sentence Planning Using Description, which generates collocations within the paradigm of sentence planning. SPUD simultaneously constructs the semantics and syntax of a sentence using a Lexicalized Tree Adjoining Grammar (LTAG). This approach captures naturally and elegantly the interaction between pragmatic and syntactic constraints on descriptions in a sentence, and the inferential and lexical interactions between multiple descriptions in a sentence. At the same time, it exploits linguistically motivated, declarative speci- fications of the discourse functions of syntactic constructions to make contextually appropriate syntactic choices.

Templates are a widespread natural language tech- nology that achieves believability within a narrow range of interaction and coverage. We consider templates for embodied conversational behavior. Such templates combine a specific pattern of marked-up text, specifying prosody and conversational signals as well as words, with similarly-annotated gaps that can be filled in by rule to yield a coherent contribution to a dialogue with a user. In this paper we argue that templates can give a de- signer substantial freedom to realize specific combina- tions of behaviors in interactions with users and thereby to explore the relationships among such factors as emo- tion, personality, individuality and social role.

cal practice: the enterprise of specifying information about the world for use in computer systems. Knowledge representation as a field also encompasses conceptual results that call practitioners’ attention to important truths about the world, mathematical results that allow practitioners to make these truths precise, and computational results that put these truths to work. This chapter surveys this practice and its results, as it applies to the interpretation of natural language utterances in implemented natural language processing systems. For a broader perspective on such technical practice, in all its strengths and weaknesses, see (Agre 1997). Knowledge representation offers a powerful general tool for the science of language. Computational logic, a prototypical formalism for representing knowledge about the world, is also the model for the level of logical form that linguists use to characterize the grammar of meaning (Larson and Segal 1995). And researchers from (Schank and Abelson 1977) to (Shieber 1993) and (Bos to appear) have relied crucially on such representations, and the inference methods associated with them, in articulating accounts of semantic relations in language, such as synonymy, entailment, informativeness and contradiction. The new textbooks (Blackburn and Bos 2002a, Blackburn and Bos 2002b) provide an excellent grounding in this research, and demonstrate how deeply computational ideas from knowledge representation can inform pure linguistic study. In this short chapter, I must leave much of..

Language engineers often point to tight connections between their systems’ linguistic representations and accumulated sensor data as a sign that their systems really mean what they say. While we believe such connections are an important piece in the puzzle of meaning, we argue that perceptual grounding alone does not suffice to explain the specific, stable meanings human speakers attribute to each other. Instead, human attributions of meaning depend on a process of societal grounding by which individual language speakers coordinate their perceptual experience and linguistic usage with other members of their linguistic communities. For system builders, this suggests that implementing a strategy of societal grounding would justify the attribution of bona fide linguistic meaning to a system even if it had little perceptual experience and only modest perceptual accuracy. We illustrate the importance and role of societal grounding using an implemented dialogue system that collaboratively identifies visual objects with human users.

This chapter investigates the computational consequences of a broadly Gricean view of language use as intentional activity. In this view, dialogue rests on coordinated reasoning about communicative intentions. The speaker produces each utterance by formulating a suitable communicative intention. The hearer understands it by recognizing the communicative intention behind it. When this coordination is successful, interlocutors succeed in considering the same intentions— that is, the same representations of utterance meaning—as the dialogue proceeds. In this paper, I emphasize that these intentions can be formalized; we can provide abstract but systematic representations that spell out what a speaker is trying to do with an utterance. Such representations describe utterances simultaneously as the product of our knowledge of grammar and as actions chosen for a reason. In particular, they must characterize the speaker’s utterance in grammatical terms, provide the links to the context that the grammar requires, and so arrive at a contribution that the speaker aims to achieve. Because I have implemented this formalism, we can regard it as a possible analysis of conversational processes at the level of computational theory. Nevertheless, this analysis leaves open what the nature of the biological computation involved in inference to intentions is, and what regularities in language use support this computation.

The cognitive hierarchy model is an approach to decision making in multi-agent interactions motivated by laboratory studies of people. It bases decisions on empirical assumptions about agents’ likely play and agents’ limited abilities to second-guess their opponents. It is attractive as a model of human reasoning in economic settings, and has proved successful in designing agents that perform effectively in interactions not only with similar strategies but also with sophisticated agents, with simpler computer programs, and with people. In this paper, we explore the qualitative structure of iterating best response solutions in two repeated games, one without messages and the other including communication in the form of non-binding promises and threats. Once the model anticipates interacting with sufficiently sophisticated agents with a sufficiently high probability, reasoning leads to policies that disclose intentions truthfully, and expect credibility from the agents they interact with, even as those policies act aggressively to discover and exploit other agents’ weaknesses and idiosyncrasies. Non-binding communication improves overall agent performance in our experiments.

An essential ingredient of language use is our ability to reason about utterances as intentional actions. Linguistic representations are the natural substrate for such reasoning, and models from computational semantics can often be seen as providing an infrastructure to carry out such inferences from rich and accurate grammatical descriptions. Exploring such inferences offers a productive pragmatic perspective on problems of interpretation, and promises to leverage semantic representations in more flexible and more general tools that compute with meaning.

This paper gives a new, proof-theoretic explanation of partial-order reasoning about time in a nonmonotonic theory of action. The explanation relies on the technique of lifting ground proof systems to compute results using variables and unification. The ground theory uses argumentation in modal logic for sound and complete reasoning about specifications whose semantics follows Gelfond and Lifschitz’s language. The proof theory of modal logic A represents inertia by rules that can be instantiated by sequences of time steps or events. Lifting such rules introduces string variables and associates each proof with a set of string equations; these equations are equivalent to a set of partial-order tree-constraints that can be solved efficiently. The defeasible occlusion of inertia likewise imposes partial-order constraints in the lifted system. By deriving an auxiliary partial order representation of action from the underlying logic, not the input formulas or proofs found, this paper strengthens the connection between practical planners and formal theories of action. Moreover, the general correctness of the theory of action justifies partial-order representations not only for forward reasoning from a completely specified start state, but also for explanatory reasoning and for reasoning by cases

We relate the theory of presupposition accommodation to a computational framework for reasoning in conversation. We understand presuppositions as private commitments the speaker makes in using an utterance but expects the listener to recognize based on mutual information. On this understanding, the conversation can move forward not just through the positive effects of interlocutors’ utterances but also from the retrospective insight interlocutors gain about one anothers’ mental states from observing what they do. Our title, ENLIGHTENED UPDATE, highlights such cases. Our approach fleshes out two key principles: that interpretation is a form of intention recognition; and that intentions are complex informational structures, which specify commitments to conditions and to outcomes as well as to actions. We present a formalization and implementation of these principles for a simple conversational agent, and draw on this case study to argue that pragmatic reasoning is holistic in character, continuous with common-sense reasoning about collaborative activities, and most effectively characterized by associating specific, reliable interpretive constraints directly with grammatical forms. In showing how to make such claims precise and to develop theories that respect them, we illustrate the general place of computation in the cognitive science of language.