Maria Carla Galavotti

Harold Jeffreys' ideas on the interpretation of probability and epistemology are reviewed. It is argued that with regard to the interpretation of probability, Jeffreys embraces a version of logicism that shares some features of the subjectivism of Ramsey and de Finetti. Jeffreys also developed a probabilistic epistemology, characterized by a pragmatical and constructivist attitude towards notions such as ‘objectivity’, ‘reality’ and ‘causality’. 1 Introductory remarks 2 The interpretation of probability 3 Jeffreys' probabilistic epistemology.

This paper investigates the kind of empiricism combined with an operationalist perspective that, in the first decades of our Century, gave rise to a turning point in theoretical physics and in probability theory. While quantum mechanics was taking shape, the classical (Laplacian) interpretation of probability gave way to two divergent perspectives: frequentism and subjectivism. Frequentism gained wide acceptance among theoretical physicists. Subjectivism, on the other hand, was never held to be a serious candidate for application to physical theories, despite the fact that its philosophical back-ground strongly resembles that underlying quantum mechanics, at least according to the Copenhagen interpretation. The reasons for this are explored.

This volume sheds light on still unexplored issues and raises new questions in the main areas addressed by the philosophy of science. Bringing together selected papers from three main events, the book presents the most advanced scientific results in the field and suggests innovative lines for further investigation. It explores how discussions on several notions of the philosophy of science can help different scientific disciplines in learning from each other. Finally, it focuses on the relationship between Cambridge and Vienna in twentieth century philosophy of science. The areas examined in the book are: formal methods, the philosophy of the natural and life sciences, the cultural and social sciences, the physical sciences, and the history of the philosophy of science.

The papers collected here comprise the proceedings of a Workshop in honor ofMerrilee and Wes Salmon, held in Florence on May 17-18, 1996. The aim of the meeting was to pay homage to these two American scholars, whose contact with Italian and European Universities and Institutes had a major influence on "Continental" thought in the field of epistemology and probability. In fact, Merrilee and Wes spent various periods lecturing at the Universities of Bologna, Florence, Rome, Trieste, Catania and Pisa, as well as in the University of Constance, where they helped to build a strong cultural "bridge" with the Pittsburgh Center for the Philosophy of Science. The Florence Center for the History and Philosophy of Science is particularly thankful to the Salmons for their ongoing cooperation and frequent visits. We must not forget that Wes Salmon was in the Florence Center and at the Philosophy Department of Florence, as visiting scholar, on many occasions, and that he made important contributions which have later appeared in Italian journals, such as Iride and Rivista di jilosojia. Merrilee was a speaker at the Conference on "Genetics, Linguistics, and Archaeology" (May 20-24,1991), organized by the Florence Center. Both Wes and Merrilee often enlivened the arguments of the initiatives they took part in.

Galavotti begins her book by stressing the centrality of probability to a whole range of philosophical problems. She writes 1: "Probability invests all branches of philosophical investigation, from epistemology to moral and political philosophy, and impinges upon major controversies, like that between determinism and indeterminism, or between free will and moral obligation, and problems such as: ‘What degree of certainty can human knowledge attain?’ ‘What is the relationship between probability and certainty?’" She then explains that her book will focus on the interpretation of the notion of probability. Chapter 1 contains some general remarks about the notion of probability, and Chapter 2 presents a brief introduction to the formal calculus of probability. Then in the next five chapters Galavotti presents in turn the five main interpretations of probability, namely the classical, frequency, propensity, logical, and subjective.Galavotti's approach to the material is historical. She traces, through extensive quotations from, and discussions of, the principal authors, the development of each of the interpretations. In many cases, she deals with early advocates of the position who are often omitted, such as De Morgan, Boole, and Jevons in the case of the logical interpretation, and Donkin in the case of the subjective interpretation. At the same time, the story is often brought right up to the present with discussions of recent authors such as Richard Jeffrey and Patrick Suppes in the case of the subjective interpretation. Galavotti's book is an excellent advertisement for the virtues of …

The proceedings of a June 1995 conference in Luino, Italy. One poem and 16 papers explore various issues in the philosophy of science with an emphasis on the foundations of probability and statistics and quantum mechanics. The topics include subjective probability, Bayesian statistics, probability kinematics, causal decision making, and probability and realism in quantum mechanics. The problem of collecting new evidence and updating probability judgements are addressed in reference to different applications. No index. Reprinted from Erkenntnis vol. 45, nos. 2-3 (1996). Annotation copyrighted by Book News, Inc., Portland, OR.

Pragmatism, taken not just as a philosophical movement but as a way of addressing problems, strongly influenced the debate on the foundations of probability during the first half of the twentieth century. Upholders of different interpretations of probability such as Hans Reichenbach, Ernest Nagel, Rudolf Carnap, Frank Ramsey, and Bruno de Finetti, acknowledged their debt towards pragmatist philosophers, including Charles Sanders Peirce, William James, Clarence Irving Lewis, William Dewey and Giovanni Vailati. In addition, scientist-philosophers like Ernst Mach, Ludwig Boltzmann, Henri Poincaré, Pierre Duhem, and Karl Pearson, who heralded a conception of science and knowledge at large that was close to pragmatism, were very influential in that debate. Among the main interpretations of probability – frequentism, propensionism, logicism and subjectivism -, the latter is no doubt the closest to the pragmatist outlook. This paper concentrates on three representatives of the subjective theory, namely Frank Ramsey, Bruno de Finetti and Émile Borel.

The First International Congress for the Unity of Science (Congrès international de philosophie scientifique) held in Paris in 1935 hosted two sessions devoted to “Induction” and “Probability” respectively. Outstanding representatives of the movement for scientific philosophy read papers in those sessions: the one on Induction hosted papers by Hans Reichenbach, Moritz Schlick, and Rudolf Carnap, while the one on Probability hosted papers by Reichenbach, Bruno de Finetti, Zygmunt Zawirski, Schlick, and Janina Hosiasson—in that order. The topics addressed concern the nature of scientific laws, the problem of meaning, and the principle of empiricism, together with the related issue of confirmation of scientific hypotheses. The nature of probability was also addressed, covering all major interpretations, namely logicism, frequentism, and subjectivism. The possibility of building a probability logic was also explored. In this paper, the contributions delivered at the sessions on Induction and Probability are surveyed, based on the version published in the fourth volume of the proceedings.

The philosophy of science took shape as an autonomous discipline in the first decades of the Twentieth Century in connection with the movement known as logical positivism or logical empiricism. According to logical empiricists philosophy of science ought to perform a “rational reconstruction” aimed at exhibiting the logical structure of scientific theories and inferential processes involved in the acquisition of scientific knowledge. While focusing on the syntactical and semantical aspects of scientific language, logical empiricists left out of the realm of the philosophy of science the sociological and psychological aspects of theory formation, as well as all methodological aspects belonging to experimentation. Starting from the early Sixties this conception gradually changed, and philosophy of science underwent a radical transformation, leading to a significant broadening of its scope. New issues and problems were addressed, belonging to fields neglected by the traditional approach. This paper sketches the main features of the discipline as it is understood today as opposed to its traditional outlook, and suggests that the term “philosophy of the sciences” is better suited than “philosophy of science” to describe its present state.

Probabilistic epistemology holds that probability is an essential ingredient of science and human knowledge at large, and that induction is a necessary constituent of the scientific method. Developed in some detail by a number of authors including Patrick Suppes, Richard Jeffrey and Brian Skyrms, this view has been embraced by so many, as to gradually become predominant. While probabilistic epistemology has been growing, awareness of its origins was somehow left behind. Probabilistic epistemology is usually seen as a product of the encounter of logical empiricism with American pragmatism. Without denying the impact of such an encounter, it is argued that the probabilistic approach was already part of the European scenario before the dissolution of logical empiricism in the late 1930s. Notably, such an approach is not linked to a particular interpretation of probability, having been endorsed by upholders of different probability notions, including Janina Hosiasson, Frank Plumpton Ramsey, Bruno de Finetti, Harold Jeffreys, and Hans Reichenbach, to mention only those authors whose contribution is addressed here. The list could extend to the French probabilists Émile Borel and Maurice Fréchet, and others not considered in this survey. The work of so many authors operating at the four corners of Europe in the first decades of the 19th century reflects a European tradition in probabilistic epistemology, somewhat overshadowed in the literature by the attention paid to logical empiricism

Probability as understood today, namely as a quantitative notion expressible by means of a function ranging in the interval between 0–1, took shape in the mid-17th century, and presents both a mathematical and a philosophical aspect. Of these two sides, the second is by far the most controversial, and fuels a heated debate, still ongoing. After a short historical sketch of the birth and developments of probability, its major interpretations are outlined, by referring to the work of their most prominent representatives. The final section addresses the question of whether any of such interpretations can presently be considered predominant, which is answered in the negative.

This paper explores the impact of pragmatism on logical empiricism in connection with the debate on the foundations of probability. Peirce ’s conception of probability, anticipating the propensity interpretation launched by Popper in the late 1950s, is recalled together with the multifarious influence he had on a number of authors including Nagel, Reichenbach, and Ramsey. This is followed by a discussion of the impact of C.I. Lewis ’s viewpoint on Carnap, to conclude with an overview of de Finetti ’s deeply pragmatist perspective.