Online research in philosophy

We present an approach to database update as a form of non monotonic temporal reasoning, the main idea of which is the (circumscriptive) minimization of changes with respect to a set of facts declared persistent by default. The focus of the paper is on the relation between this approach and the update semantics recently proposed by Katsuno and Mendelzon. Our contribution in this regard is twofold: • We prove a representation theorem for KM semantics in terms of a restricted subfamily of the operators defined by our construction. • We show how the KM semantics can be generalized by relaxing our construction in a number of ways, each justified in certain intuitive circumstances and each corresponding to one specific postulate. It follows that there are reasonable update operators outside the KM family. • Our approach is not dependent for its plausibility on this connection with KM semantics. Rather, it provides a relatively rich and flexible framework in which the frame and ramification problems can be solved in a systematic way by reasoning about default persistence of facts.

Dynamic update of information states is a new paradigm in logicalsemantics. But such updates are also a traditional hallmark ofprobabilistic reasoning. This note brings the two perspectives togetherin an update mechanism for probabilities which modifies state spaces.

Formal learning theory constitutes an attempt to describe and explain the phenomenon of learning, in particular of language acquisition. The considerations in this domain are also applicable in philosophy of science, where it can be interpreted as a description of the process of scientific inquiry. The theory focuses on various properties of the process of hypothesis change over time. Treating conjectures as informational states, we link the process of conjecture-change to epistemic update. We reconstruct and analyze the temporal aspect of learning in the context of dynamic and temporal logics of epistemic change. We first introduce the basic formal notions of learning theory and basic epistemic logic. We provide a translation of the components of learning scenarios into the domain of epistemic logic. Then, we propose a characterization of finite identifiability in an epistemic temporal language. In the end we discuss consequences and possible extensions of our work.

In a classic paper Partee (1973) noted detailed referential and anaphoric parallels between tenses and pronouns in English. Since then these parallels have been successfully analyzed in terms of domain-neutral principles of discourse reference and anaphora — most fully developed in Kamp & Reyle (1993) — which apply uniformly to referents of various logical types. These include ordinary individuals (the kings and cabbages sort) as well as times, events and states. The referential parallel has long been known to extend even further, to the modal domain — a discovery due to Kaplan (1978). More recently, the anaphoric parallel has likewise been extended. At the intuitive level, there is now consensus that individuals and possibilities are on a par for the purposes of reference and anaphora. But it remains an open question whether the formal analogue of an individual in the modal domain — in intuitive terms, a possibility — is a possible world (as in Kaplan 1978, Schlenker 1999), a class of possible worlds (Stone 1997) or a dynamic update (e.g., Frank & Kamp 1997). Orthogonal to this issue, it has also been observed that in all semantic domains some referents are more central than others, in the sense of the centering theory of Grosz et al (1995). For example, Stone & Hardt (1997) show that ‘sloppy’ ellipsis in English generalizes across all semantic domains, and that it can be uniformly analyzed as strict discourse anaphora to center-sensitive referents, with the illusion of sloppiness due to center shift. In this paper I first present crosslinguistic evidence that the parallels between individuals and possibilities are indeed pervasive. Moreover, the centering parallels are even more detailed than has so far been recognized. These parallels favor the view that a possibility — the modal analogue of an individual — is best analyzed as a class of possible worlds, as in Stone (1997). Adopting this view, I then develop a semantic representation language, which I call Logic of Change with Centered Worlds, in which the observed cross-domain parallels can be formally explicated..

Natural languages exhibit a great variety of grammatical paradigms. For instance, in English verbs are grammatically marked for tense, whereas in the tenseless Eskimo-Aleut language Kalaallisut they are marked for illocutionary mood. Although time is a universal dimension of the human experience and speaking is part of that experience, some languages encode reference to time without any grammatical tense morphology, or reference to speech acts without any illocutionary mood morphology. Nevertheless, different grammatical systems are semantically parallel in certain respects. Specifically, I propose that English tenses form a temporal centering system, which monitors and updates topic times, whereas Kalaallisut moods form a modal centering system, which monitors and updates modal discourse referents. To formalize these centering parallels I define a dynamic logic that represents not only changing information but also changing focus of attention in discourse (Update with Centering, formalizing Grosz et al 1995). Different languages can be translated into this typed logic by directly compositional universal rules of Combinatory Categorial Grammar (CCG) The resulting centering theory of tense and illocutionary mood draws semantic parallels across different grammatical systems. The centering generalizations span the extremes of the typological spectrum, so they are likely to be universal. In addition, the theory accounts for the translation equivalence of tense and illocutionary mood in a given utterance context. Following Stalnaker (1978) I assume that the very act of speaking up has a ‘commonplace effect’ on the context. It focuses attention on the speech act and thereby introduces default modal and temporal topics. These universal defaults complement language-specific grammars, e.g. English tenses and Kalaallisut moods. In a given utterance context the universal discourse-initial defaults plus language-specific grammatical marking may add up to the same truth conditions..

TEXT: D. and A. Bolles, 1996, A Grammar of the Yucatecan Mayan Language/The Expoloits of Juan Thul, The Trickster Rabbit. http://www.famsi.org/reports/96072/grammar/section42.html. GLOSSES & TRANSLATION: See the text pdf at http://www.rci.rutgers.edu/~mbittner/ym.html. ONLINE UPDATE: See Bittner 2004 ‘Online Update: Quantified de se and polysynthesis’. The following table lists some basic symbols of the semantic representation language to be used.

Update semantics1 embodies a radical view on the relation between context and interpretation. The meaning of a sentence is identified with its context change potential, where contexts are identified with information states. The recursive definition of semantic interpretation is stated in terms of a process of updating an information state with a sentence. Meanings of sentences, then, are update functions. In general, these are partial functions, since the possibility to update with a sentence may depend on the fulfillment of certain constraints (presuppositions, the presence of antecedents for anaphora, etc.). It is important to note that context and interpretation are interdependent: the interpretation process depends on the context, `.

Update semantics1 embodies a radical view on the relation between context and interpretation. The meaning of a sentence is identified with its context change potential, where contexts are identified with information states. The recursive definition of semantic interpretation is stated in terms of a process of updating an information state with a sentence. Meanings of sentences, then, are update functions. In general, these are partial functions, since the possibility to update with a sentence may depend on the fulfillment of certain constraints (presuppositions, the presence of antecedents for anaphora, etc.). It is important to note that context and interpretation are interdependent: the interpretation process depends on the context, `.

It has long been recognized that temporal anaphora in French and English depends on the aspectual distinction between events and states. For example, temporal location as well as temporal update depends on the aspectual type. This paper presents a general theory of aspect-based temporal anaphora, which extends from languages with grammatical tenses (like French and English) to tenseless languages (e.g. Kalaallisut). This theory also extends to additional aspect-dependent phenomena and to non-atomic aspectual types, processes and habits, which license anaphora to proper atomic parts (cf. nominal pluralities and kinds).

The central claim of this paper is that surface-faithful word-by-word update is feasible and desirable, even in languages where word order is supposedly free. As a first step, in sections 1 and 2, I review an argument from Bittner 2001a that semantic composition is not a static process, as in PTQ, but rather a species of anaphoric bridging. But in that case the context-setting role of word order should extend from cross-sentential discourse anaphora to sentence-internal anaphoric composition. This can be spelled out as a two-part hypothesis. First, in all languages anaphoric composition derives incremental updates based on the topological order rather than the syntactic hierarchy. And secondly, rigid vs. free word order is simply rigid vs. free mapping from syntax to topology. To formalize this hypothesis, I first present, in section 3, Sevensorted Logic of Change with Centering. This makes it possible, in section 4, to articulate a system of constraints on basic meanings in Kalaallisut — a polysynthetic language with free word order, ideally suited to test the hypothesis of incremental update. The key assumptions about topology as the input to anaphoric composition are spelled out in section 5, which concludes the development of a general formal framework. This formal framework then serves, in sections 6 through 8, t o explicate topologically based incremental updates for increasingly more complex samples of an actual Kalaallisut text. This reveals ubiquitous patterns of prominence-guided anaphora, in all semantic domains, t o increasingly more complex types of discourse referents. These anaphoric patterns show that the context-setting role of word order indeed does extend from discourse to word-to-word anaphora. And this, in turn, strongly supports the hypothesis of topologically based anaphoric composition. Finally, in section 9 I adduce evidence from English that this hypothesis also holds for languages with rigid word order, albeit the fixed mapping keeps the topology close to the syntax. I conclude that both free and rigid word orders receive a natural account if semantic composition is viewed as topologically based anaphoric bridging..