Bas C. Van Fraassen

In a traditional view of science we come to fully believe the main accepted theories . Some of the hypotheses "possible for all that science tells us" seem more likely than others: enter probability as grading the possibilities left open. Probabilism contends with this tradition. Richard Jeffrey told us never to resolve doubt but only to quantify it, and to give maximal probability only to tautologies. Despite severe difficulties, I shall argue that the traditional view is reconcilable with probabilism. I will propose a single unified account with conditional personal probability as basic, allowing for full belief in empirical theories, with our probabilities grading the possibilities left open.

El inspirador Relational Quantum Mechanicsde Carlo Rovelli cumple varios propósitosde manera simultánea: proporciona unanueva visión de cómo es el mundo de lamecánica cuántica y ofrece un programapara derivar el formalismo de la teoría deun conjunto de postulados simples quepertenecen al procesamiento de la información.Enesteartículopropongoquenosconcentremostotalmente en lo primero,para explorar el mundo de la mecánicacuántica tal como lo representa Rovelli.Es un mundo fascinante, en parte debidoa la dependencia de Rovelli sobre el enfoquedelateoríadelainformaciónparalosfundamentosdelamecánicacuántica,yen parte debido a que su presentaciónimplica asumir una postura en un partefundamental en la filosofía misma.Ca r l o Ro v e l l i ’ s i n s p i r i n g Re l a t i o n a lQuantum Mechanics serves several aims atonce: it provides a new vision of what theworld of quantum mechanics is like, andit offers a program to derive the theory’sformalism from a set of simple postulatespertai ni ng to i nformati on processi ng.I propose here to concentrate entirelyon the former, to explore the world ofquantum mechanics as Rovelli depicts it.It is a fascinating world in part becauseof Rovelli’s reliance on the informationtheory approach to the foundations ofquantum mechanics, and in part becauseits presentation involves taking sides on afundamental divides within philosophyitself

Professor Roeper adresses a large question, whether probabilistic semantics is a kind of semantics at all. Happily, he does this via an exploration of a specific issue on which he and Professor Leblanc have done important work. That is the issue of how the relationship of logical consequence can be characterized as a relation denned in terms of probability. Let us follow him in calling a relevant relationship of the latter sort the degree of implication, and follow Professor Roeper on his quest for a satisfactory one.

Thomason (1979/2010)’s argument against competence psychologism in semantics envisages a representation of a subject’s competence as follows: he understands his own language in the sense that he can identify the semantic content of each of its sentences, which requires that the relation between expression and content be recursive. Then if the scientist constructs a theory that is meant to represent the body of the subject’s beliefs, construed as assent to the content of the pertinent sentences, and that theory satisfies certain ‘natural assumptions’, then it implies that the subject is inconsistent if the beliefs include arithmetic. I challenge the result by insisting that the motivation for Thomason’s principle (ii), via Moore’s Paradox, leads to a more complex representation, in which stating the facts and expressing one’s beliefs are treated differently. Certain logical connections among expressions of assent, and between expression and statement, are a matter of consequence on pain of pragmatic incoherence, not consequence on pain of classical logical inconsistency. But while this salvages the possibility that a modification of the above sort of representation could be adequate, Thomason’s devastating conclusion returns if the scientist identifies himself as the subject of that representation, even when paying heed to the requirement of pragmatic coherence of the sort highlighted by Moore’s Paradox.

An innovative, multifaceted approach to scientific experiments as designed by and shaped through interaction with the modeling process The role of scientific modeling in mediation between theories and phenomena is a critical topic within the philosophy of science, touching on issues from climate modeling to synthetic models in biology, high energy particle physics, and cognitive sciences. Offering a radically new conception of the role of data in the scientific modeling process as well as a new awareness of the problematic aspects of data, this cutting-edge volume offers a multifaceted view on experiments as designed and shaped in interaction with the modeling process. Contributors address such issues as the construction of models in conjunction with scientific experimentation; the status of measurement and the function of experiment in the identification of relevant parameters; how the phenomena under study are reconceived when accounted for by a model; and the interplay between experimenting, modeling, and simulation when results do not mesh. Highlighting the mediating role of models and the model-dependence of data measurement, this volume proposes a normative and conceptual innovation in scientific modeling--that the phenomena to be investigated and modeled must not be precisely identified at the start but specified during the course of the interactions arising between experimental and modeling activities. Contributors: Nancy D. Cartwright, U of California, San Diego; Anthony Chemero, U of Cincinnati; Ronald N. Giere, U of Minnesota; Jenann Ismael, U of Arizona; Tarja Knuuttila, U of South Carolina; Andrea Loettgers, U of Bern, Switzerland; Deborah Mayo, Virginia Tech; Joseph Rouse, Wesleyan U; Paul Teller, U of California, Davis; Michael Weisberg, U of Pennsylvania; Eric Winsberg, U of South Florida.

These are the proceedings of the Workshop on Quantum Logic held in Erice (Sicily), December 2 - 9, 1979, at the Ettore Hajorana Centre for Scientific Culture. A conference of this sort was originally proposed by Giuliano Toraldo di Francia, who suggested the idea to Antonino Zichichi, and thus laid the foundation for the Workshop. To both of them we express our appreciation and thanks, also on behalf of the other participants, for having made this conference possible. There were approximately fifty participants; their names and institutions are listed in the text. Quantum logic, which has now a history of some forty or more years, has seen remarkable growth during the sixties and seventies. The papers in the present volume presuppose, by and large, some acquaintance with the elements of the subject. These may be found in the well-known books by J.H. Jauch (Foundations of Quantum Hechanics; Reading, 1968), V.S. Varadarajan (Geometry of Quantum Theory: Princeton, 1968), and C. Piron (Foundations of Quantum Theory; New York, 1976). The initial program for the conference listed about twenty-five invited papers. But in the context of a very active and qualified attendance, other contributions were offered. This volume contains all of them. The program listed six main topics: I. Classification or different areas of quantum logic, and open problems. II. Comparison and unification of different approaches to quantum theories; problems of interpretation. III. Formal quantum logic; axiomatics. IV. Hodal interpretations of quantum logic. v vi FOREWORD V. Quantum set theory.