The logic of historical necessity as founded on two-dimensional modal tense logic

We consider a version of so called T × W logic for historical necessity in the sense of R.H. Thomason (1984), which is somewhat special in three respects: (i) it is explicitly based on two-dimensional modal logic in the sense of Segerberg (1973); (ii) for reasons of applicability to interesting fields of philosophical logic, it conceives of time as being discrete and finite in the sense of having a beginning and an end; and (iii) it utilizes the technique of systematic frame constants in order to handle the problem of irreflexivity in tense logics, well known since Gabbay (1981). Axiomatizations are given for two infinite hierarchies of two-dimensional modal tense logics, one without and one with the characteristic operators for historical necessity and possibility. Strong and weak completeness results are obtained for both hierarchies as well as a result to the effect that two approaches to their semantics are equivalent, much in the spirit of Di Maio and Zanardo (1996) and von Kutschera (1997).     

A two-dimensional logic for diagonalization and the a priori

Synthese - Two-dimensional semantics, which can represent the distinction between a priority and (one kind of) necessity, has wielded considerable influence in the philosophy of language. In this...     

A logic for epistemic two-dimensional semantics

Epistemic two-dimensional semantics is a theory in the philosophy of language that provides an account of meaning which is sensitive to the distinction between necessity and apriority. While this theory is usually presented in an informal manner, I take some steps in formalizing it in this paper. To do so, I define a semantics for a propositional modal logic with operators for the modalities of necessity, actuality, and apriority that captures the relevant ideas of epistemic two-dimensional semantics. I also describe some properties of the logic that are interesting from a philosophical perspective, and apply it to the so-called nesting problem.     

The logic of algebraic rules as a generalization of equational logic

In this paper we start an investigation of a logic called the logic of algebraic rules. The relation of derivability of this logic is defined on universal closures of special disjunctions of equations extending the relation of derivability of the usual equational logic. The paper contains some simple theorems and examples given in justification for the introduction of our logic. A number of open questions is posed.     

Quantum logic as a dynamic logic

We address the old question whether a logical understanding of Quantum Mechanics requires abandoning some of the principles of classical logic. Against Putnam and others (Among whom we may count or not E. W. Beth, depending on how we interpret some of his statements), our answer is a clear “no”. Philosophically, our argument is based on combining a formal semantic approach, in the spirit of E. W. Beth’s proposal of applying Tarski’s semantical methods to the analysis of physical theories, with an empirical–experimental approach to Logic, as advocated by both Beth and Putnam, but understood by us in the view of the operational- realistic tradition of Jauch and Piron, i.e. as an investigation of “the logic of yes–no experiments” (or “questions”). Technically, we use the recently-developed setting of Quantum Dynamic Logic (Baltag and Smets 2005, 2008) to make explicit the operational meaning of quantum-mechanical concepts in our formal semantics. Based on our recent results (Baltag and Smets 2005), we show that the correct interpretation of quantum-logical connectives is dynamical, rather than purely propositional. We conclude that there is no contradiction between classical logic and (our dynamic reinterpretation of) quantum logic. Moreover, we argue that the Dynamic-Logical perspective leads to a better and deeper understanding of the “non-classicality” of quantum behavior than any perspective based on static Propositional Logic.     

Rich deontic logic: a preliminary study

This paper begins the development of new types of deontic operators, particularly ones whose semantic characterization is based on models with forward-branching time. In such models, supplemented by a choice function to model human agency, and an obligation function to introduce normative features, it is possible to develop a rich language with a variety of obligation operators, differing from one another in how they relate to time, and to the causal conditions, the causal consequences, and the logical consequences of actions. We approach these concepts making extensive use of the notion of a transition, as introduced in [M. Xu, Synthese 112 (1997) 137].     

Babies' logic activity: a differential study

From a neuroconstructivist point of view based on infant cognitive development, the aim of this study is to get to know and compare the logical organization and content of the spontaneous activity of babies with alternative developmental courses (typical babies and Down's Syndrome ones). A fundamental form of logic is observed since the beginning of babies' interaction with their environment. This protologic is constructed through their organised and significative activity with the environment and it results in the elaboration of logico-mathematical and physical knowledge. Using Systematic Observation, we recorded the spontaneous activity of n=20 babies, (n=10 typical babies, n=10 Down Syndrome babies), with a cognitive developmental level of 1; 3 years (15 months). Microgenetical and statistical analyses were applied and the results obtained showed a reduced logical content and organization of the activity of Down's Syndrome babies, which corroborates and amplifies the results of previous research works. These results make evident the need to plan early educational intervention in order to optimize babies' developmental resources.     

Discursive logic towards a logic of rational discourse

Both logic and philosophy of science investigate formal aspects of scientific discourse, i.e. properties of (non-monotonic) consequence operations for discursive logic. In the present paper we handle two of them: paraconsistency and enthymematycity.Supported by grants from the Alexander von Humboldt-Stiftung, form the Fulbright-Foundation and from the Center for Philosophy of Science at the University of Pittsburgh.Presented byJan Zygmunt