It is widely agreed on that most cognitive processes are contextual in the sense that they depend on the environment, or context, inside which they are carried on. Even concentrating on the issue of contextuality in reasoning, many different notions of context can be found in the Artificial Intelligence literature. Our intuition is that reasoning is usually performed on a subset of the global knowledge base. The notion of context is used as a means of formalizing this idea of localization. Roughly speaking, we take a context to be the set of facts used locally to prove a given goal plus the inference routines used to reason about them (which in general are different for different sets of facts). Our perspective is similar to that proposed in [McC87, McC91]. The goal of this paper is to propose an epistemologically adequate theory of reasoning with contexts. The emphasis is on motivations and intuitions, rather than on technicalities. The two basic definitions are reported i...

Introduction As language users humans possess a culturally transmitted system of unparalleled complexity in the natural world. Linguistics has revealed over the past 40 years the degree to which the syntactic structure of language in particular is strikingly complex. Furthermore, as Pinker and Bloom point out in their agenda-setting paper Natural Language and Natural Selection \grammar is a complex mechanism tailored to the transmission of propositional structures through a serial interface" (Pinker and Bloom, 1990, 707). These sorts of observations, along with inuential arguments from linguistics and psychology about the innateness of language (see, e.g. Chomsky, 1986; Pinker, 1994), have led many authors to the conclusion that an explanation for the origin of syntax must invoke neo-Darwinian natural selection. \Evolutionary theory oers clear criteria for when a trait should be attributed to natural selection: complex design for some function, and the absence of alternative proc

Anchoring is the process of creating and maintaining the correspondence between symbols and percepts that refer to the same physical objects. Although this process must necessarily be present in any physically embedded system that includes a symbolic component (e.g., an autonomous robot), no systematic study of anchoring as a problem per se has been reported in the literature on intelligent systems. In this paper, we propose a domain-independent definition of the anchoring problem, and identify its three basic functionalities: find, reacquire, and track. We illustrate our definition on two systems operating in two different domains: an unmanned airborne vehicle for traffic surveillance; and a mobile robot for office navigation.

Anchoring is the problem of connecting, inside an artificial system, symbols and sensor data that refer to the same physical objects in the external world. This problem needs to be solved in any robotic system that incorporates a symbolic component. However, it is only recently that the anchoring problem has started to be addressed as a problem per se, and a few general solutions have begun to appear in the literature. This paper introduces the special issue on perceptual anchoring of the Robotics and Autonomous Systems journal. Our goal is to provide a general overview of the anchoring problem, and highlight some of its subtle points.

Syntactic structure constrains the possible "coreference " relations between the noun phrases in a sentence. Since the early days of generative syntax, we have learned a great deal about the nature of these structural constraints. Much of this syntactic theorizing has been possible with only a vague and informal understanding of what it really is in semantic terms that is being constrained here. Everyone agrees that it is not coreference in a literal sense, i.e., sameness of referents. But to specify in positive and semantically precise terms what it is instead has turned out to be non-trivial. Those authors that have given serious attention to the semantic import of syntactic constraints on so-called "coreference " have arrived at rather different conclusions. 1 A particularly elegant and well-elaborated proposal in this regard is due to Tanya Reinhart (1983a; 1983b). I ts central thesis is that only one type of "coreference " relation is syntactically represented and directly constrained by principles of grammar, and this is the well-understood relation of variable binding in the sense of formal logic. Other semantic relations, in particular such

The modern computational lexical semantics reached a point in its development when it has become necessary to define the premises and goals of each of its several trends. This paper proposes ten choices in terms of which these premises and goals can be discussed. It is argued that the central questions include the use of lexical rules for generating word senses; the role of syntax, pragmatics, and formal semantics in the specification of lexical meaning; the use of a world model, or ontology, as the organizing principle for lexical-semantic descriptions; the use of rules with limited scope; the relation between static and dynamic resources; the commitment to descriptive coverage; the trade-off between generalization and idiosyncracy; and, finally, the adherence to the "supply-side" (method-oriented) or "demand-side" (task-oriented) ideology of research. The discussion is inspired by, but not limited to, the comparison between the generative lexicon approach and the ontologi...

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this paper I shall sketch a view of information updates in dialogue as opposed to the classical view of updating in monologic discourses. I will suggest that the semantic analysis of attitudes (such as belief and knowledge) are central to updates in dialogue and point to some parallels between traditional puzzles that have been addressed within the philosophical literature on the attitudes and phenomena that arise in dialogue semantics. Finally, I will present a sketch of a way of representing information states that appears to meet requirements for both analyses of the attitudes and dialogue updates. Our view of information states (which is a revision of that presented in Cooper, 1996, Cooper and Ginzburg, 1996) blends together ideas from computer science, linguistics and logic. 2 Updates The notion of information update has become standard in a number of modern semantic theories including work by Irene Heim (Heim, 1982), discourse representation theory (DRT) (Kamp and Reyle, 1993), and dynamic semantics as it has been developed in Amsterdam and elsewhere (Groenendijk and Stokhof, 1991, Dekker, 1993). For a recent paper bringing these approaches together see van Eijck and Kamp (1997). The classical view of information update as presented in these papers is of update in a text or monologue which can be represented diagramatically as in (1). (1) Information state 1 + utterance

. One of the most interesting puzzles in formalizing belief contexts is the fact that many belief reports can be given both an opaque and a transparent readings. A traditional explanation is that the two readings are related to the failure and success of the principle of substitutivity respectively, and this in turn is explained with the de re/de dicto distinction. We propose an alternative analysis, based on the idea that another agent's beliefs can just be quoted (preserving opacity) or translated into the reporter's language (allowing for transparency). We show that MultiContext systems allow for the formalization of these two phenomena at the same time, thanks to their multi-language feature. 1 Beliefs and Substitutivity A very important capability is reasoning about our own and other people's beliefs. We have beliefs about our beliefs; we learn from other people's beliefs; we accept (don't accept) other people's beliefs among our beliefs; we share our beliefs with other people; ...

Gottlob Frege (1892) is credited with the so-called “principle of compositionality”, also called “Frege’s Principle”, which one often hears expressed this way: Frege’s Principle (so-called) “The meaning of a sentence is a function of the meanings of the words in it and the way they are combined syntactically.” (Exactly how Frege himself understood “Frege’s Principle ” is not our concern here; 1 rather, it is the understanding that this slogan has acquired in contemporary linguistics that we want to pursue, and this has little further to do with Frege.) But why should linguists care what compositionality is or whether natural languages “are compositional ” or not? 2.1.1 An “Empirical Issue”? Often we hear that “compositionality is an empirical issue ” (meaning the question whether natural language is compositional or not)—usually asserted as a preface to expressing skepticism about a “yes ” answer. In the most general sense of Frege’s Principle, however, the fact that natural languages are compositional is beyond any serious doubt. Consider that: