This essay presents a philosophical and computational theory of the representation of de re, de dicto, nested, and quasi-indexical belief reports expressed in natural language. The propositional Semantic Network Processing System (SNePS) is used for representing and reasoning about these reports. In particular, quasi-indicators (indexical expressions occurring in intentional contexts and representing uses of indicators by another speaker) pose problems for natural-language representation and reasoning systems, because--unlike pure indicators--they cannot be replaced by coreferential NPs without changing the meaning of the (...) embedding sentence. Therefore, the referent of the quasi-indicator must be represented in such a way that no invalid coreferential claims are entailed. The importance of quasi-indicators is discussed, and it is shown that all four of the above categories of belief reports can be handled by a single representational technique using belief spaces containing intensional entities. Inference rules and belief-revision techniques for the system are also examined. (shrink)

A serial context-free grammar logic is a normal multimodal logic L characterized by the seriality axioms and a set of inclusion axioms of the form □tφ→□s1…□skφ. Such an inclusion axiom corresponds to the grammar rule t → s1… sk. Thus the inclusion axioms of L capture a context-free grammar . If for every modal index t, the set of words derivable from t using is a regular language, then L is a serial regular grammar logic. In this paper, we present (...) an algorithm that, given a positive multimodal logic program P and a set of finite automata specifying a serial regular grammar logic L, constructs a finite least L-model of P. A least L-model M of P has the property that for every positive formula φ, P ⊧ φ iff M ⊧ φ. The algorithm runs in exponential time and returns a model with size 2O. We give examples of P and L, for both of the case when L is fixed or P is fixed, such that every finite least L-model of P must have size 2Ω. We also prove that if G is a context-free grammar and L is the serial grammar logic corresponding to G then there exists a finite least L-model of □s p iff the set of words derivable from s using G is a regular language. (shrink)

In this paper, an objective conception of contexts based loosely upon situation theory is developed and formalized. Unlike subjective conceptions, which take contexts to be something like sets of beliefs, contexts on the objective conception are taken to be complex, structured pieces of the world that (in general) contain individuals, other contexts, and propositions about them. An extended first-order language for this account is developed. The language contains complex terms for propositions, and the standard predicate "ist" that expresses the relation (...) that holds between a context and a proposition just in case the latter is true in the former. The logic for the objective conception features a global classical predicate calculus, a local logic for reasoning within contexts, and axioms for propositions. The specter of paradox is banished from the logic by allowing "ist" to be nonbivalent in problematic cases: it is not in general the case, for any context c and proposition p, that either ist(c,p) or ist(c, ¬p). An important representational capability of the logic is illustrated by proving an appropriately modified version of an illustrative theorem from McCarthy's classic Blocks World example. (shrink)

This article is oriented toward the use of modality in artificial intelligence (AI). An agent must reason about what it or other agents know, believe, want, intend or owe. Referentially opaque modalities are needed and must be formalized correctly. Unfortunately, modal logics seem too limited for many important purposes. This article contains examples of uses of modality for which modal logic seems inadequate.I have no proof that modal logic is inadequate, so I hope modal logicians will take the examples as (...) challenges. (shrink)

The logical omniscience problem, whereby standard models of epistemic logic treat an agent as believing all consequences of its beliefs and knowing whatever follows from what else it knows, has received plenty of attention in the literature. But many attempted solutions focus on a fairly narrow specification of the problem: avoiding the closure of belief or knowledge, rather than showing how the proposed logic is of philosophical interest or of use in computer science or artificial intelligence. Sentential epistemic logics, as (...) opposed to traditional possible worlds approaches, do not suffer from the problems of logical omniscience but are often thought to lack interesting epistemic properties. In this paper, I focus on the case of rule-based agents, which play a key role in contemporary AI research but have been neglected in the logical literature. I develop a framework for modelling monotonic, nonmonotonic and introspective rule-based reasoners which have limited cognitive resources and prove that the resulting models have a number of interesting properties. An axiomatization of the resulting logic is given, together with completeness, decidability and complexity results. (shrink)

From the Editor’s Introduction: "The Internal Limitations of Human Understanding." We carry, unavoidably, the limits of our understanding with us. We are perpetually confined within the horizons of our conceptual structure. When this structure grows or expands, the breadth of our comprehensions enlarges, but we are forever barred from the wished-for glimpse beyond its boundaries, no matter how hard we try, no matter how much credence we invest in the substance of our learning and mist of speculation. -/- The limitations (...) in view here are not due to the mere finitude of our understanding of ourselves and of the world in which we live. They are limitations that come automatically and necessarily with any form of understanding. They are, as we shall see, part and parcel of any organization or ordering of data that we call information. -/- The consequences of these limitations are varied: As a result of them, hermeneutics cannot help but be hermetic; scientific theories of necessity are circumscribed by the boundaries of the ideas that define them; formal systems must choose between consistency and comprehensiveness; philosophical study, because it includes itself within its own proper subject matter, is forced to be reflexive in its self-enclosure. The fundamental dynamic shared by all forms of understanding testifies to an internal limitative keystone. (shrink)

As a step towards comprehensive computer models of communication, and effective human machine dialogue, some of the relationships between communication and affect are explored. An outline theory is presented of the architecture that makes various kinds of affective states possible, or even inevitable, in intelligent agents, along with some of the implications of this theory for various communicative processes. The model implies that human beings typically have many different, hierarchically organized, dispositions capable of interacting with new information to produce affective (...) states, distract attention, interrupt ongoing actions, and so on. High "insistence" of motives is defined in relation to a tendency to penetrate an attention filter mechanism, which seems to account for the partial loss of control involved in emotions. One conclusion is that emulating human communicative abilities will not be achieved easily. Another is that it will be even more difficult to design and build computing systems that reliably achieve interesting communicative goals. (shrink)

This essay describes computational semantic networks for a philosophical audience and surveys several approaches to semantic-network semantics. In particular, propositional semantic networks are discussed; it is argued that only a fully intensional, Meinongian semantics is appropriate for them; and several Meinongian systems are presented.

Problem setting. Modern IT technologies consolidate a new attitude to legal knowledge, which from a technological point of view is a "raw material" for artificial legal systems. Technological approach to legal knowledge can not be identified with technology or method, as it is a special operational system of legal acts with legal knowledge for the purpose of its translation from society into an artificial dialogue system, in particular intellectual. Therefore, it is necessary to study the cognitive and informational aspects of (...) the movement of legal knowledge, in particular, their means of obtaining, the mechanisms for selection, dissemination, transformation, accumulation, translation and application, as well as ways to automate these complex processes based on modern high-tech digital devices. We are talking about little-known and extremely topical issues of processing legal knowledge and transforming them into an active information resource. These problems require comprehensive, multidimensional comprehension. Recent research and publications analysis. The results of the analysis of scientific sources and publications indicate that these trends require a deep and thorough study of the particularities of the practical relationship to legal knowledge. New information technologies have contributed to the development of the idea of the diversity of human knowledge. The results of the research of these problems give an opportunity to note that, in general, systematic scientific comprehension of the complex, volumetric and multidimensional problems of practical relevance to legal knowledge need further study. Paper objectiv. The purpose of this article is to consider certain aspects of the practical relation to legal knowledge based on the results of understanding this issue by various representatives of the humanities and interdisciplinary researchers. Paper main body. The article substantiates that the practical attitude to legal knowledge with the advent of artificial intellectual systems has highlighted the problem of extracting, representing and using knowledge in the field of jurisprudence. It is revealed that new information technologies have translated the issues of the specifics of human knowledge, the peculiarities of the interrelation of its main levels into the plane of practical problems associated with the transformation of personal knowledge into formalized. It is determined that the practical attitude towards legal knowledge cannot be identified with either technology or method. It is shown that the attitude towards knowledge as a resource includes the operation of "extracting" knowledge from an expert. The questions are analyzed how and in what way the subject can become aware of the implicit components of personal knowledge. Conclusions of the research. Technological attitude to legal knowledge - mandatory stage in the design of artificial intelligence systems, which includes an action on the study of the microenvironment, as well as the design of the intellectual basis of the computer, so that the latter becomes a quasi-subject in communication with the user, that is, the computer understands the system's requests, stores the subject of the dialogue, knowledge of the subject area and poorly structured problems, secondary texts - the arguments of one or another computer solution. The analysis of technological attitude to legal knowledge requires new methodological schemes. Technological attitude to legal knowledge is not identical neither with formalization, nor with algorithmic methodology. The methodology of technological relation to legal knowledge is a complex problem that can be solved on the basis of a constructive dialogue between the developers of artificial intelligence systems and lawyers. The structure of knowledge is fundamentally complex, it includes various facts from the relevant field of law, the relationship between them, the rules of action, knowledge of how to include knowledge in the artificial intelligence system. All this translates into the specifics of human knowledge, the peculiarities of the relationship between its main levels in the area of actual practical problems that require the attention of scholars, therefore the prospects for further research in this direction are directly related to the study of the structure of knowledge in the field of law. (shrink)

Ascribing mental qualities like beliefs, intentions and wants to a machine is sometimes correct if done conservatively and is sometimes necessary to express what is known about its state. We propose some new definitional tools for this: definitions relative to an approximate theory and second order structural definitions.