In this paper, we describe a collaborative information retrieval method among personal repositorie and an implementation of the method on a personal agent framework. We propose a framework for personal agents that aims to enable the sharing and exchange of information resources that are distributed unevenly among individuals. The kernel of a personal agent framework is an RDF(resource description framework)-based information repository for storing, retrieving and manipulating privately collected information, such as documents the user read and/or wrote, email he/she exchanged, (...) web pages he/she browsed, etc. The repository also collects annotations to information resources that describe relationships among information resources and records of interaction between the user and information resources. Since the information resources in a personal repository and their structure are personalized, information retrieval from other users' is an important application of the personal agent. A vector space model with a personalized concept-base is employed as an information retrieval mechanism in a personal repository. Since a personalized concept-base is constructed from information resources in a personal repository, it reflects its user's knowledge and interests. On the other hand, it leads to another problem while querying other users' personal repositories; that is, simply transferring query requests does not provide desirable results. To solve this problem, we propose a query equalization scheme based on a relevance feedback method for collaborative information retrieval between personalized concept-bases. In this paper, we describe an implementation of the collaborative information retrieval method and its user interface on the personal agent framework. (shrink)

Modal realism -- Time, space, world -- Existence -- Actuality -- Modal realism and modal tense -- Transworld individuals and their identity -- Existensionalism -- Impossibility -- Proposition and relief -- Fictional worlds -- Epistemology.

Mark Jago’s four arguments against Takashi Yagisawa’s extended modal realism are examined and shown to be ineffective. Yagisawa’s device of modal tense renders three of Jago’s arguments harmless, and the correct understanding of predications of modal properties of world stages blocks the fourth one.

Sherlock Holmes is a fictional individual. So is his favorite pipe. Our pre-theoretical intuition says that neither of them is real. It says that neither of them really, or actually, exists. It also says that there is a sense in which they do exist, namely, a sense in which they exist “in the world of” the Sherlock Holmes stories. Our pre-theoretical intuition says in general of any fictional individual that it does not actually exist but exists “in the world of” (...) the relevant fiction. I wish to defend this pretheoretical intuition. To do so, I need to defend two claims: that fictional individuals do not actually exist, and that they exist “in the world of” the relevant fiction. The aim of this paper is to defend the first claim. (shrink)

It may appear that in order to be any way at all, a thing must exist. A possible – worlds version of this claim goes as follows: (E) For every x, for every possible world w, Fx at w only if x exists at w. Here and later in (R), the letter ‘F’ is used as a schematic letter to be replaced with a one – place predicate. There are two arguments against (E). The first is by analogy. Socrates is (...) widely admired now but he does not exist now. So, it is not the case that for every x, for every time t, Fx at t only if x exists at t. Possible worlds are analogous to times. Therefore, (E) is false (cf., Kaplan 1973: 503 – 05 and Salmon 1981: 36 – 40). For the second argument, replace ‘F’ with ‘does not exist’. (E) then says that for every x, for every possible world w, x does not exist at w only if x exists at w. This is obviously false. Therefore (E) is false (cf., Kaplan 1977: 498). Despite their considerable appeal, these arguments are not unassailable. The first argument suffers from the weakness inherent in any argument from analogy; the analogy it rests on may not.. (shrink)

Deep theorizing about possibility requires theorizing about possible objects. One popular approach regards the notion of a possible object as intertwined with the notion of a possible world. There are two widely discussed types of theory concerning the nature of possible worlds: actualist representationism and possibilist realism. They support two opposing views about possible objects. Examination of the ways in which they do so reveals difficulties on both sides. There is another popular approach, which has been influenced by the philosophy (...) of Alexius Meinong. The Meinongian approach is relevant to theorizing about possible objects because it attempts to construct a general theory of objects other than ordinary concrete existing objects. Independently of the debate about the nature of possible worlds or about Meinongianism, it is not always as straightforward as it may at first appear to determine whether putative possible objects are indeed possible. Another category of object similar to that of a possible object is the category of a fictional object. Although initially attractive, the idea that fictional objects are possible objects should not be accepted blindly. An important instance of theoretical usefulness of possible objects is their central role in the validation of two controversial theorems of a simple quantified modal logic. (shrink)

This article contributes to the critical engagement with luck egalitarianism by advancing two arguments. Firstly, it questions the cogency of the dichotomies – e.g., luck/choice, person/circumstance, agency/structure – and the accompanying moral ideal of pure voluntarism. This makes it difficult for luck egalitarianism to dissect appropriately the inequalities embedded in social relations, such as social networks and involuntary associations, in which voluntariness and contingency as well as agency and structure are intertwined. Secondly, it suggests that the relational approach, which has (...) been developed, inter alia, in the empirical study of inequality, provides a morally and practically adequate perspective on egalitarian justice. The relational approach achieves this by converging upon those in‐between social relations that are irreducible to the macro‐level structure and to micro‐level agency. Moreover, a relationally sensitive perspective on inequality can adeptly respond to the difficulties that luck‐egalitarian theories encounter. (shrink)

Those who object to David Lewis' modal realism express qualms about philosophical respectability of the Lewisian notion of a possible world and its correlate notion of an inhabitant of a possible world. The resulting impression is that these two notions either stand together or fall together. I argue that the Lewisian notion of a possible world is otiose even for a good Lewisian modal realist, and that one can carry out a good Lewisian semantics for modal discourse without Lewisian possible (...) worls. I do so by generalizing Lewis' own idea that restrictions on quantification come and go with the pragmatic wind and relativizing possible worlds as shifting domains of discourse. I then suggest a way to soften the infamous incredulous stare. (shrink)

Modal Dimensionalism is a metaphysical theory about possible worlds that is naturally suggested by the often-noted parallelism between modal logic and tense logic. It says that the universe spreads out not only in spatiotemporal dimensions but also in a modal dimension. It regards worlds as nothing more or less than indices in the modal dimension in the way analogous to the way in which Temporal Dimensionalism regards temporal points and intervals as indices in the temporal dimension. Despite its naturalness and (...) intuitive appeal. Modal Dimensionalism has been largely ignored while the debates between David Lewis and his critics have dominated the discourse on the nature of possible worlds. It is high time that we took Modal Dimensionalism seriously as a viable alternative. (shrink)

There was a time when 'logic' just meant classical logic. The climate is slowly changing and non-classical logic cannot be dismissed off-hand. However, a metatheory used to study the properties of non-classical logic is often classical. In this paper, we will argue that this practice of relying on classical metatheories is problematic. In particular, we will show that it is a bad practice because the metatheory that is used to study a non-classical logic often rules out the very logic it (...) is designed to study. (shrink)

What does it mean for the laws of logic to fail? My task in this paper is to answer this question. I use the resources that Routley/Sylvan developed with his collaborators for the semantics of relevant logics to explain a world where the laws of logic fail. I claim that the non-normal worlds that Routley/Sylvan introduced are exactly such worlds. To disambiguate different kinds of impossible worlds, I call such worlds logically impossible worlds. At a logically impossible world, the laws (...) of logic fail. In this paper, I provide a definition of logically impossible worlds. I then show that there is nothing strange about admitting such worlds. (shrink)