On the Predicate Logic of Linear Kripke Frames and some of its Extensions

We propose a new, rather simple and short proof of Kripke-completeness for the predicate variant of Dummett's logic. Also a family of Kripke-incomplete extensions of this logic that are complete w.r.t. Kripke frames with equality (or equivalently, w.r.t. Kripke sheaves [8]), is described.     

A Theory of Hypermodal Logics: Mode Shifting in Modal Logic

A hypermodality is a connective whose meaning depends on where in the formula it occurs. The paper motivates the notion and shows that hypermodal logics are much more expressive than traditional modal logics. In fact we show that logics with very simple K hypermodalities are not complete for any neighbourhood frames.     

On Łukasiewicz's Four-Valued Modal Logic

ukasiewicz's four-valued modal logic is surveyed and analyzed, together with ukasiewicz's motivations to develop it. A faithful interpretation of it in classical (non-modal) two-valued logic is presented, and some consequences are drawn concerning its classification and its algebraic behaviour. Some counter-intuitive aspects of this logic are discussed in the light of the presented results, ukasiewicz's own texts, and related literature.     

Razonamiento diagnóstico con conceptos modales

Resumen

Se presentan los resultados obtenidos por estudiantes de BUP y universitarios de Historia y Psicología en dos tareas de clasificación y razonamiento diagnóstico en las que se han utilizado los conceptos modales de verdad, posibilidad y necesidad. Se parte del supuesto de que la lógica modal puede resultar de utilidad para describir el razonamiento diagnóstico sobre información en la que aparecen dichos conceptos modales.

Los resultados muestran que, sobre este tipo de tareas, los estudiantes universitarios han obtenido una mejor ejecución que los de BUP; y los estudiantes de Psicología, mejor que los de Historia. En general, los sujetos han tendido a utilizar estrategias verificacionistas de sus hipótesis y a considerar la base de conocimientos que se les proporcionaba como completa en cuanto a la información que contenía. Esto, unido a las dificultades para manejar la información expresada de forma negativa, ha producido un cierto número de falacias lógicas y de conclusiones incorrectas, tales como problemas en el manejo de los condicionales, conclusiones imprudentes y poco conservadoras, etc. No obstante las deficiencias encontradas, se concluye que las lógicas modales pueden resultar de utilidad para describir y simular el razonamiento diagnóstico de los sujetos, especialmente si se les añaden algunas reglas funcionamiento por defecto.     

Getting Moral Luck Right

Moral luck, until recently, has been understood either explicitly or implicitly through using a lack of control account of luck. For example, a case of resultant moral luck is a case where an agent is morally blameworthy or more morally blameworthy or praiseworthy for an outcome despite that outcome being significantly beyond that agent's control (Nagel 1993). Due to a shift in understanding the concept of luck itself in terms of modal robustness, however, other accounts of moral luck have surfaced. Both Duncan Pritchard (2006) and Julia Driver (2013) have offered an alternative way of understanding moral luck by employing versions of a modal account of luck. This essay considers some problems with these accounts and attempts to resolve them.     

Presentism: Foreigner-Friendly or Xenophobic?

I argue that, for all we know, there are perfectly ordinary actual entities that are temporal in the usual sense and yet never present, past, or future. This epistemic fact requires us to modify the theses of presentism and eternalism. More importantly, it generates three new and quite serious objections to presentism, which I formulate and partially evaluate in this paper.