Complexity Results of STIT Fragments

We provide a Kripke semantics for a STIT logic with the ??next?? operator. As the atemporal group STIT is undecidable and unaxiomatizable, we are interested in strict fragments of atemporal group STIT. First we prove that the satisfiability problem of a formula of the fragment made up of individual coalitions plus the grand coalition is also NEXPTIME-complete. We then generalize this result to a fragment where coalitions are in a given lattice. We also prove that if we restrict the language to nested coalitions the satisfiability problem is NP-complete if the number of agents is fixed and PSPACEcomplete if the number of agents is variable. Finally we embed individual STIT with the ??next?? operator into a fragment of atemporal group STIT.     

Is artefactualness a value-relevant property of living things?

Artefacts are often regarded as being mere things that possess only instrumental value. In contrast, living entities (or some subset of them) are often regarded as possessing some form of intrinsic (or non-instrumental) value. Moreover, in some cases they are thought to possess such value precisely because they are natural (i.e., non-artefactual). However, living artefacts are certainly possible, and they may soon be actual. It is therefore necessary to consider whether such entities should be regarded as mere things (like most non-living artefacts) or as possessing intrinsic value (like many, if not all) living entities. That is, it is necessary to determine whether artefactualness is a value-relevant property with respect to the intrinsic value of living things.     

Theory structuralism in a rigid framework

This paper develops the first parts of a logical framework for the empirical sciences, by means of a redefinition of theory structuralism as originally developed by Joseph Sneed, Wolfgang Stegmüller, and others, in the context of a ??rigid?? logic as based on a fixed (therefore rigid) ontology. The paper defends a formal conception of the empirical sciences that has an irreducible ontological basis and is unable, in general, to provide purely structural characterizations of the domain of a theory. The extreme rationalist utopia of a characterization of the real world ??up to isomorphism??, therefore, is rejected.     

“Inference versus consequence” revisited: inference, consequence, conditional, implication

Inference versus consequence, an invited lecture at the LOGICA 1997 conference at Castle Liblice, was part of a series of articles for which I did research during a Stockholm sabbatical in the autumn of 1995. The article seems to have been fairly effective in getting its point across and addresses a topic highly germane to the Uppsala workshop. Owing to its appearance in the LOGICA Yearbook 1997, Filosofia Publishers, Prague, 1998, it has been rather inaccessible. Accordingly it is republished here with only bibliographical changes and an afterword.     

Branching time, indeterminism and tense logic

This paper deals with the historical and philosophical background of the introduction of the notion of branching time in philosophical logic as it is revealed in the hitherto unpublished mail-correspondence between Saul Kripke and A.N. Prior in the late 1950s. The paper reveals that the idea was first suggested by Saul Kripke in a letter to A.N. Prior, dated September 3, 1958, and it is shown how the elaboration of the idea in the course of the correspondence was intimately intervowen with considerations of how to represent indeterminism and of the adequacy of tensed logic in light of special relativity. The correspondence underpins the point that Prior??s later development of branching time may be understood as a crucial part of his attempt at the formulating a conceptual framework integrating basic human notions of time and free choice.     

Preface

The contributions in this part of the present issue mainly originate from the Carnap Lectures 2011 in Bochum where Prof. Tim Crane (Cambridge, UK) and Prof. Katalin Farkas (Budapest) presented keynote lectures under the heading ??The Boundaries of the Mental??. The full workshop program is available on our website: http://www.ruhr-uni-bochum.de/philosophy/carnap2011/index.html     

Naming and categorizing objects: Task differences modulate the polarity of semantic effects in the picture–word interference paradigm

The picture-word interference paradigm is a prominent tool for studying lexical retrieval during speech production. When participants name the pictures, interference from semantically related distractor words has regularly been shown. By contrast, when participants categorize the pictures, facilitation from semantically related distractors has typically been found. In the extant studies, however, differences in the task instructions (naming vs. categorizing) were confounded with the response level: While responses in naming were typically located at the basic level (e.g., "dog"), responses were located at the superordinate level in categorization (e.g., "animal"). The present study avoided this confound by having participants respond at the basic level in both naming and categorization, using the same pictures, distractors, and verbal responses. Our findings confirm the polarity reversal of the semantic effects--that is, semantic interference in naming, and semantic facilitation in categorization. These findings show that the polarity reversal of the semantic effect is indeed due to the different tasks and is not an artifact of the different response levels used in previous studies. Implications for current models of language production are discussed.