The present anthology has its origin in two international conferences that were arranged at Uppsala University in August 2004: "Logicism, Intuitionism and F- malism: What has become of them?" followed by "Symposium on Constructive Mathematics." The rst conference concerned the three major programmes in the foundations of mathematics during the classical period from Frege's Begrif- schrift in 1879 to the publication of Godel' ] s two incompleteness theorems in 1931: The logicism of Frege, Russell and Whitehead, the intuitionism of Brouwer, and Hilbert's formalist and proof-theoretic programme. The main purpose of the conf- ence was to assess the relevance of these foundational programmes to contemporary philosophy of mathematics. The second conference was announced as a satellite event to the rst, and was speci cally concerned with constructive mathematics-an activebranchofmathematicswheremathematicalstatements-existencestatements in particular-are interpreted in terms of what can be effectively constructed. C- structive mathematics may also be characterized as mathematics based on intuiti- isticlogicand, thus, beviewedasadirectdescendant ofBrouwer'sintuitionism. The two conferences were successful in bringing together a number of internationally renowned mathematicians and philosophers around common concerns. Once again it was con rmed that philosophers and mathematicians can work together and that real progress in the philosophy and foundations of mathematics is possible only if they do. Most of the papers in this collection originate from the two conferences, but a few additional papers of relevance to the issues discussed at the Uppsala c- ferences have been solicited especially for this volume."

Stig Kanger (1924-1988) made important contributions to logic and formal philosophy. Kanger's dissertation Provability in Logic, 1957, contained significant results in proof theory as well as the first fully worked out model-theoretic interpretation of quantified modal logic. It is generally accepted nowadays that Kanger was one of the originators of possible worlds semantics for modal logic. Kanger's most original achievements were in the areas of general proof theory, the semantics of modal and deontic logic, and the logical analysis of the concept of rights. He also contributed to action theory, preference logic, and the theory of measurement. This is the first of two volumes dedicated to the work of Stig Kanger. The present volume is a complete collection of Kanger's philosophical papers. The second volume contains critical essays on Kanger's work, as well as biographical essays on Kanger written by colleagues and friends.

Stig Kanger (1924-1988) made important contributions to logic and formal philosophy. Kanger's most original achievements were in the areas of general proof theory, the semantics of modal and deontic logic, and the logical analysis of the concept of rights. But he contributed significantly to action theory, preference logic and the theory of measurement as well. This is the second of two volumes dedicated to the work of Stig Kanger. The first volume is a complete collection of Kanger's philosophical papers. The present volume contains critical essays on the various aspects of Kanger's work as well as some biographical sketches. Lennart A...qvist, Jan Berg, Brian Chellas, Anatoli Degtyarev, Lars Gustafsson, SAren HalldA(c)n, Kaj BA, rge Hansen, Sven Ove Hansson, Risto Hilpinen, Jaakko Hintikka, Ghita HolmstrAm-Hintikka, Lars Lindahl, Sten LindstrAm, Ingmar PArn, Dag Prawitz, Wlodek Rabinowicz, Krister Segerberg, Amartya Sen, SAren Stenlund, GAran Sundholm, and Andrei Voronkov have contributed to this volume.

The present volume has its origin in a meeting of philosophers, linguists and cognitive scientists that was held at Umea University, Sweden, September 24-26, 1993. The meeting was organized by the Department of Philosophy in cooperation with the Department of Linguistics, and it was called UmLLI-93, the Umea Colloquium on Dynamic Approaches in Logic, Language and Information. The papers published here are considerably expanded and revised versions of talks presented by invited speakers at this colloquium. The papers included here fall into three broad categories. In the first part of the book, Action, we have collected papers that concern the formal theory of action, the logic of nonns, and the theory of rational decision. The papers in the second part, Belief Change, concern the theory of belief dynamics in the tradition of Alchourr6n, Gardenfors and Makinson. The third part, Cognition, concerns abstract questions about knowledge and truth as well'as more concrete questions about the usefuleness and tractability of various graphic representations of infonnation. An additional and important topic of the colloquium concerned logical approaches to natural language. For the sake of the thematic unity of this book, and its appearance in the series Trends in logic, the colloquium papers related to language are not included here, but some of these contributions will appear in the philosophical journal Theoria.

The present anthology has its origin in two international conferences that were arranged at Uppsala University in August 2004: "Logicism, Intuitionism and F- malism: What has become of them?" followed by "Symposium on Constructive Mathematics." The rst conference concerned the three major programmes in the foundations of mathematics during the classical period from Frege's Begrif- schrift in 1879 to the publication of Godel' ] s two incompleteness theorems in 1931: The logicism of Frege, Russell and Whitehead, the intuitionism of Brouwer, and Hilbert's formalist and proof-theoretic programme. The main purpose of the conf- ence was to assess the relevance of these foundational programmes to contemporary philosophy of mathematics. The second conference was announced as a satellite event to the rst, and was speci cally concerned with constructive mathematics-an activebranchofmathematicswheremathematicalstatements-existencestatements in particular-are interpreted in terms of what can be effectively constructed. C- structive mathematics may also be characterized as mathematics based on intuiti- isticlogicand, thus, beviewedasadirectdescendant ofBrouwer'sintuitionism. The two conferences were successful in bringing together a number of internationally renowned mathematicians and philosophers around common concerns. Once again it was con rmed that philosophers and mathematicians can work together and that real progress in the philosophy and foundations of mathematics is possible only if they do. Most of the papers in this collection originate from the two conferences, but a few additional papers of relevance to the issues discussed at the Uppsala c- ferences have been solicited especially for this volume."

Stig Kanger (1924-1988) made important contributions to logic and formal philosophy. Kanger's most original achievements were in the areas of general proof theory, the semantics of modal and deontic logic, and the logical analysis of the concept of rights. But he contributed significantly to action theory, preference logic and the theory of measurement as well. This is the second of two volumes dedicated to the work of Stig Kanger. The first volume is a complete collection of Kanger's philosophical papers. The present volume contains critical essays on the various aspects of Kanger's work as well as some biographical sketches. Lennart A...qvist, Jan Berg, Brian Chellas, Anatoli Degtyarev, Lars Gustafsson, SAren HalldA(c)n, Kaj BA, rge Hansen, Sven Ove Hansson, Risto Hilpinen, Jaakko Hintikka, Ghita HolmstrAm-Hintikka, Lars Lindahl, Sten LindstrAm, Ingmar PArn, Dag Prawitz, Wlodek Rabinowicz, Krister Segerberg, Amartya Sen, SAren Stenlund, GAran Sundholm, and Andrei Voronkov have contributed to this volume.

Stig Kanger (1924-1988) made important contributions to logic and formal philosophy. Kanger's dissertation Provability in Logic, 1957, contained significant results in proof theory as well as the first fully worked out model-theoretic interpretation of quantified modal logic. It is generally accepted nowadays that Kanger was one of the originators of possible worlds semantics for modal logic. Kanger's most original achievements were in the areas of general proof theory, the semantics of modal and deontic logic, and the logical analysis of the concept of rights. He also contributed to action theory, preference logic, and the theory of measurement. This is the first of two volumes dedicated to the work of Stig Kanger. The present volume is a complete collection of Kanger's philosophical papers. The second volume contains critical essays on Kanger's work, as well as biographical essays on Kanger written by colleagues and friends.