The first introductory textbook on description logics, relevant to computer science, knowledge representation and the semantic web.

In this paper, we investigate the relationship between two decidable interval-based temporal description logics that have been proposed in the literature, T L-ALCF and ALCF. Although many aspects of these two logics are quite similar, the two logics suggest two rather different paradigms for representing temporal conceptual knowledge. In this paper, we exhibit a reduction from T L-ALCF concepts to ALCF concepts that serves two purposes: first, it nicely illustrates the relationship between the two knowledge representation paradigms; and second, it (...) provides a tight PSPACE upper bound for T L-ALCF concept satisfiabiliy, whose complexity was previously unknown. (shrink)

Propositional dynamic logic (PDL) is one of the most successful variants of modal logic. To make it even more useful for applications, many extensions of PDL have been considered in the literature. A very natural and useful such extension is with negation of programs. Unfortunately, as long-known, reasoning with the resulting logic is undecidable. In this paper, we consider the extension of PDL with negation of atomic programs, only. We argue that this logic is still useful, e.g. in the context (...) of description logics, and prove that satisfiability is decidable and EXPTIME-complete using an approach based on Büchi tree automata. (shrink)

In 1984, Danecki proved that satisfiability in IPDL, i.e., Propositional Dynamic Logic (PDL) extended with an intersection operator on programs, is decidable in deterministic double exponential time. Since then, the exact complexity of IPDL has remained an open problem: the best known lower bound was the ExpTime one stemming from plain PDL until, in 2004, the first author established ExpSpace-hardness. In this paper, we finally close the gap and prove that IPDL is hard for 2-ExpTime, thus 2-ExpTime-complete. We then sharpen (...) our lower bound, showing that it even applies to IPDL without the test operator interpreted on tree structures. (shrink)

The aim of this paper is to construct a tableau decision algorithm for the modal description logic K ALC with constant domains. More precisely, we present a tableau procedure that is capable of deciding, given an ALC-formula with extra modal operators (which are applied only to concepts and TBox axioms, but not to roles), whether is satisfiable in a model with constant domains and arbitrary accessibility relations. Tableau-based algorithms have been shown to be practical even for logics of rather high (...) complexity. This gives us grounds to believe that, although the satisfiability problem for K ALC is known to be NEXPTIME-complete, by providing a tableau decision algorithm we demonstrate that highly expressive description logics with modal operators have a chance to be implementable. The paper gives a solution to an open problem of Baader and Laux [5]. (shrink)

We study satisfiability and infinite-state model checking in ICPDL, which extends Propositional Dynamic Logic (PDL) with intersection and converse operators on programs. The two main results of this paper are that (i) satisfiability is in 2EXPTIME, thus 2EXPTIME-complete by an existing lower bound, and (ii) infinite-state model checking of basic process algebras and pushdown systems is also 2EXPTIME-complete. Both upper bounds are obtained by polynomial time computable reductions to ω-regular tree satisfiability in ICPDL, a reasoning problem that we introduce specifically (...) for this purpose. This problem is then reduced to the emptiness problem for alternating two-way automata on infinite trees. Our approach to (i) also provides a shorter and more elegant proof of Danecki's difficult result that satisfiability in IPDL is in 2EXPTIME. We prove the lower bound(s) for infinite-state model checking using an encoding of alternating Turing machines. (shrink)

As a remedy for the bad computational behaviour of first-order temporal logic (FOTL), it has recently been proposed to restrict the application of temporal operators to formulas with at most one free variable thereby obtaining so-called monodic fragments of FOTL. In this paper, we are concerned with constructing tableau algorithms for monodic fragments based on decidable fragments of first-order logic like the two-variable fragment or the guarded fragment. We present a general framework that shows how existing decision procedures for first-order (...) fragments can be used for constructing a tableau algorithm for the corresponding monodic fragment of FOTL. Some example instantiations of the framework are presented. (shrink)

According to ordinary language philosophy (OLP), philosophical problems can be solved by investigating ordinary language, often because the problems stem from its misuse. According to ideal language philosophy (ILP), on the other hand, philosophical problems exist because ordinary language is flawed and has to be improved or replaced by constructed languages that do not exhibit these flaws. OLP and ILP together make up linguistic philosophy, the view that philosophical problems are problems of language. Linguistic philosophy is opposed to what may (...) be called, for lack of a better word, ‘traditional philosophy’ (TP), the view that philosophical problems can be solved by discovering non-linguistic facts. In the following, OLP, ILP, and TP are taken to be methodologies, that is, frameworks in which to interpret and evaluate different philosophical methods (i.e., argumentative strategies). The two linguistic methodologies are discussed separately with TP as a foil, and then used to interpret the status of different philosophical methods. While each of the methods discussed here finds a plausible interpretation in each methodology, there are other arguments for and against linguistic philosophy in general, and for and against ILP and OLP in particular. As none of these arguments is decisive, I conclude with a superficial moral about peaceful co-existence. (shrink)

PLoS ONE 3(3): e1897. doi:10.1371/journal.pone.

In recent years, the full text of papers are increasingly available electronically which opens up the possibility of quantitatively investigating citation contexts in more detail. In this study, we introduce a new form of citation analysis, which we call citation concept analysis (CCA). CCA is intended to reveal the cognitive impact certain concepts—published in a highly-cited landmark publication—have on the citing authors. It counts the number of times the concepts are mentioned (cited) in the citation context of citing publications. We (...) demonstrate the method using three classical highly cited books: (1) The structure of scientific revolutions by Thomas S. Kuhn, (2) The logic of scientific discovery—Logik der Forschung: Zur Erkenntnistheorie der modernen Naturwissenschaft in German—, and (3) Conjectures and refutations: the growth of scientific knowledge by Karl R. Popper. It is not surprising—as our results show—that Kuhn’s “paradigm” concept seems to have had a significant impact. What is surprising is that our results indicate a much larger impact of the concept “paradigm” than Kuhn’s other concepts, e.g., “scientific revolution”. The paradigm concept accounts for about 40% of the concept-related citations to Kuhn’s work, and its impact is resilient across all disciplines and over time. With respect to Popper, “falsification” is the most used concept derived from his books. Falsification is the cornerstone of Popper’s critical rationalism. (shrink)

Representative for contemporary attempts to establish a science of consciousness we examine Chalmers' statement and resolution of the 'hard problem of consciousness'. Agreeing with him that in order to account for subjectivity it is necessary to expand the ontology of the natural sciences, we argue that it is not sufficient to just add conscious experience to the list of fundamental features of the world. Instead, we turn to phenomenology as the philosophy of conscious experience and give an outline of Merleau-Ponty's (...) critique of the objectivist ontology underlying science which excludes subjectivity from the world. We reconstruct his proposal for a revised ontology in The Visible and the Invisible aiming at an extended understanding of Being including subjectivity, which takes on the form of a constellation of new ontological terms centered around the concept of the 'flesh of the world'. Trying to spell out the consequences of Merleau-Ponty's ontological considerations for scientific practice and especially the science of consciousness, we notice that his philosophy of subjectivity-in-the-world on its part is unable to connect to the insights of the natural sciences. The phenomenological critique of the 'hard problem' reveals a deeper disparity which, at present, limits its practical implications. (shrink)

When experimental philosophers carry out studies on thought experiments, some participants are excluded based on certain exclusion criteria, mirroring standard social science vignette methodology. This involves excluding people that do not pay attention or who miscomprehend the scenario presented in thought experiments. However, experimental philosophy studies sometimes exclude an alarmingly high number of participants. We argue that this threatens the external and internal validity of the conclusions being drawn and we show how a simple visualization of thought experiments can reduce (...) exclusion rates significantly. Furthermore, we argue that focus should not merely be on how many are excluded, but also why they are excluded, and we highlight the role of comprehension questions in this regard. Philosophical thought experiments often rely on the acceptance of certain key premises that may be regarded contestable, and asking comprehension questions involving such key assumptions could be problematic as that may result in some participants being inadvertently excluded from the study, potentially creating a selection bias. (shrink)

Self-fulfillment of theories is argued to be a threat to social science in at least two ways. First, a realist might worry that self-fulfillment constitutes a threat to the idea that social science is a proper science consistent with a realist approach that develops true and successful statements about the world. Second, one might argue that the potential self-fulfilling nature of social science theories potentially undermines the ethical integrity of social scientists. We argue that if one accepts that social science (...) theories are not based on laws akin to those that govern natural reality or acknowledges that if one can predict self-fulfillment via a meta-theory that explains the underlying regularities of the self-fulfilling change, the threat to realism is dismantled. Furthermore, on the basis of these arguments, we show that if one is unable to predict the consequences of a theory, it is difficult to ascribe moral responsibility at the individual level. It is, therefore, not the potential self-fulfillment of theories per se that poses an ethical challenge, in contrast to claims in the literature. (shrink)

This essay examines relativist and fideist challenges to Alasdair MacIntyre’s theory of rationality by reading some of MacIntyre’s more recent works in thecontext of his earlier work in the philosophy of religion, Marxism, and the philosophy of the social sciences.

In this study the relationship of religiosity and value priorities is differentiated, based on a multidimensional measurement of different contents of religiosity. The structure of values is conceptualized using Schwartz' two orthogonal dimensions of Self-transcendence vs. Self-enhancement and Openness to change vs. Conservation. The relations between these two dimensions and eight religious contents, ranging from open-minded to more close-minded forms of religiosity, were tested in a sample of church attenders , gathered in Germany. The results show, that depending on the (...) content of religiosity, different values are preferred . The results indicate the importance of the content of religiosity for predicting value-loaded behaviors. (shrink)

Studies in experimental philosophy claim to document intuition variation. Some studies focus on demographic group-variation; Colaçoet al., for example, claim that age generates intuition variation regarding knowledge attribution in a fake-barn scenario. Other studies claim to show intuition variation when comparing the intuition of philosophers to that of non-philosophers. The main focus has been on documenting intuition variation rather than uncovering what underlying factor(s) may prompt such a phenomenon. We explore a number of suggested explanatory hypotheses put forth by Colaçoet (...) al., as well as an attempt to test Sosa's claim that intuition variance is a result of people ‘filling in the details’ of a thought experiment differently from one another. We show (i) that people respond consistently across conditions aimed at ‘filling in the details’ of thought experiments, (ii) that risk attitude does not seem relevant to knowledge ascription, (iii) that people's knowledge ascriptions do not vary due to views about defeasibility of knowledge. Yet, (iv) we find no grounds to reject that a large proportion of people appear to adhere to so-called subjectivism about knowledge, which may explain why they generally have intuitions about the fake-barn scenario that vary from those of philosophers. (shrink)

Speed is an obvious facet of contemporary society, whereas slowness has often been dismissed as conservative and antimodern. Challenging a long tradition of thought, Lutz Koepnick instead proposes we understand slowness as a strategy of the contemporary--a decidedly modern practice that gazes firmly at and into the present's velocity. As he engages with late twentieth- and early twenty-first-century art, photography, video, film, and literature, Koepnick explores slowness as a critical medium to intensify our temporal and spatial experiences. Slowness helps (...) us register the multiple layers of time, history, and motion that constitute our present. It offers a timely mode of aesthetic perception and representation that emphasizes the openness of the future and undermines any conception of the present as a mere replay of the past. Discussing the photography and art of Janet Cardiff, Olafur Eliasson, Hiroshi Sugimoto, and Michael Wesely; the films of Peter Weir and Tom Tykwer; the video installations of Douglas Gordon, Willie Doherty, and Bill Viola; and the fiction of Don DeLillo, Koepnick shows how slowness can carve out spaces within processes of acceleration that allow us to reflect on alternate temporalities and durations. (shrink)

Ralph Cudworth's (1617-1688) True Intellectual System of the Universe is considered the high point of philosophical production by the Cambridge Platonists. In this work, Cudworth compresses all of his era's core problems in natural philosophy and theology and attempts to find a comprehensive solution to broadly explain how God acts in nature. For the first time, the present work presents the complete story of how Cudworth developed his Neoplatonic system using a compatible combination of text form and content, and along (...) the way, it also unfolds a panoramic view of ancient classical philosophy. (shrink)

Aus dem Inhalt: I. BegriffeG. Gabriel, Begriff - Metapher - Katachrese. Zum Abschluss des Historischen Worterbuchs der PhilosophieH. Huhn, Unterscheidungswissen. Begriffsexplikation und BegriffsgeschichteC. Spoerhase, Prosodien des Wissens. Uber den gelehrten "Ton", 1794-1797 II. MetaphernP. Gehring, Das Bild vom Sprachbild. Die Metapher und das VisuelleD. Werle, Methodenmetaphern. Metaphorologie und ihre Nutzlichkeit fur die philologisch-historische MethodologieA. Ruth, Metaphern in der GeschichteR. Klausnitzer, Unsichtbare Faden, unsichtbare Hand. Ideengeschichte und Figuration eines MetaphernkomplexesR. Kany, Palimpsest. Konjunkturen einer EdelmetapherJ. de Salas, Communication and Metaphor in OrtegaIII. (...) ImaginationenJ. Anselm Steiger, Kontrafaktizitat und Kontrarationalitat des Glaubens in der Theologie Martin LuthersT. Verbeek, Einbildungskraft und "Mogliche Welten": Descartes und Spinoza. (shrink)

Weite Teile der katholischen Dogmatik und Fundamentaltheologie dieser Tage sind in nicht unerheblichem Maße von dem geprägt, was man”Letztbegründung“nennen könnte. Diese Denkrichtung sucht in der Tradition der Aufklärung und des deutschen Idealismus nach letzten, philosophisch ausweisbaren Gründen für die Glaubensinhalte der katholischen Theologie. Der Autor zeichnet Thomas Pröppers, Hansjürgen Verweyens und Klaus Müllers Angänge nach und prüft, ob ihr Anspruch auf einen letztgültigen Sinn gelingen kann. Die Lektüre ausgewählter Texten von Emmanuel Levinas und Jacques Derrida lässt erhebliche Zweifel am Erfolg (...) einer Letztbegründung aufkommen. Darüber hinaus gibt ein Durchgang durch lehramtliche und biblische Texte zu bedenken, ob ein solcher Anspruch theologisch überhaupt erhoben werden muss. Gilt nicht auch und gerade nach der philosophischen Aufklärung: "Mein Angesicht kannst Du nicht sehen. Nicht sieht mich der Mensch und lebt."? (shrink)

By a classifying topos for a first-order theory , we mean a topos such that, for any topos models of in correspond exactly to open geometric morphisms → . We show that not every first-order theory has a classifying topos in this sense, but we characterize those which do by an appropriate ‘smallness condition’, and we show that every Grothendieck topos arises as the classifying topos of such a theory. We also show that every first-order theory has a conservative extension (...) to one which possesses a classifying topos, and we obtain a Heyting-valued completeness theorem for infinitary first-order logic. (shrink)