Very roughly, the conditional construal of conditional probability is the hypothesis that the conditional probability P equals the probability of the conditional 'if A, then B'. My main purposes are to hone this rough statement down to various precise versions of the Hypothesis, as I call it, and to argue that virtually none of them is tenable. ;In S 1, I distinguish four versions of the Hypothesis. The subsequent four sections are largely an opinionated historical survey, tracing the motivations for (...) and origins of the Hypothesis, and its fluctuating fortunes. By the end of S 5, the first version has been shown to be refuted, and the second version moribund. ;My own negative results against the Hypothesis begin in S 6. I first generalize Lewis' so-called 'second triviality result', adding insult to injury as far as the second version is concerned. S 7 refutes the third version of the Hypothesis, and casts serious doubt on the fourth, or so I argue. I then consider four ways in which the Hypothesis could be resurrected. In S 8, I refute the first of these ways, and strengthen some old results; and in S 9 I argue against the other three ways. ;In S 10, I contend that philosophers have been in the grip of a dogma: that conditional probability is to be univocally analyzed by the usual ratio formula. I offer a positive proposal, which I call 'the ambiguity thesis': so-called 'conditional probability' is ambiguous between the usual ratio formula, and the probability of a conditional. The demise of the Hypothesis shows that these two disambiguations cannot be identified. (shrink)

Rich with historical and cultural value, these works are published unaltered from the original University of Minnesota Press editions.

Metaphysicians speak of laws of nature in terms of necessity and universality; scientists, in terms of symmetry and invariance. In this book van Fraassen argues that no metaphysical account of laws can succeed. He analyzes and rejects the arguments that there are laws of nature, or that we must believe there are, and argues that we should disregard the idea of law as an adequate clue to science. After exploring what this means for general epistemology, the author develops the empiricist (...) view of science as a construction of models to represent the phenomena. (shrink)

Kolmogorov''s axiomatization of probability includes the familiarratio formula for conditional probability: 0).$$ " align="middle" border="0">.

Is Bayesian decision theory a panacea for many of the problems in epistemology and the philosophy of science, or is it philosophical snake-oil? For years a debate had been waged amongst specialists regarding the import and legitimacy of this body of theory. Mark Kaplan had written the first accessible and non-technical book to address this controversy. Introducing a new variant on Bayesian decision theory the author offers a compelling case that, while no panacea, decision theory does in fact have the (...) most profound consequences for the way in which philosophers think about inquiry, criticism and rational belief. The new variant on Bayesian theory is presented in such a way that a non-specialist will be able to understand it. The book also offers new solutions to some classic paradoxes. It focuses on the intuitive motivations of the Bayesian approach to epistemology and addresses the philosophical worries to which it has given rise. (shrink)

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. (shrink)

As part of his Constructive Empiricism, Van Fraassen commends agnosticism about the existence of the unobservable entities posited by the physical sciences. This position of Scientific Agnosticism is compatible with the acceptance, in his sense, of Science. For to accept Science is, he says, to accept it as empirically adequate, but to refrain from deciding between the realistically interpreted theory and the as-if variant, according to which the observations are as if the theory is correct but the theory is not (...) correct. My purpose in this paper is to argue, against van Fraassen, that we—or at least most of us—should embrace Scientific Realism not Scientific Agnosticism. (shrink)