Jenann’s central metaphysical thesis is that there is an objective conditional probability function PrG(A/B), the domain of which includes a great many, perhaps all, pairs of contingent propositions. This pair can be synchronic or diachronic: both can concern how things are at the same time, or not. Jenann’s central epistemological thesis is antiskepticism about PrG, in the following sense: prima facie, the subjective credence functions of epistemically reasonable agents converge on PrG: roughly, if you’ve done a lot of science, for (...) all A, B, your C(A/B) is similar to PrG(A/B). (Compare antiskepticism about perceptual knowledge: prima facie, if circumstances are good and one’s visual experience represents that p, p.) These theses have two cool consequences: first, the possibility of a novel approach to objective Bayesianism; second, a way of doing away with dynamical laws. (shrink)

Classic work by one of the most brilliant figures in post-war analytic philosophy.

This is a review of Jon Williamson's 'In Defence of Objective Bayesianism'.

How are we to understand the use of probability in corroboration functions? Popper says logically, but does not show we could have access to, or even calculate, probability values in a logical sense. This makes the logical interpretation untenable, as Ramsey and van Fraassen have argued. -/- If corroboration functions only make sense when the probabilities employed therein are subjective, however, then what counts as impressive evidence for a theory might be a matter of convention, or even whim. So isn’t (...) so-called ‘corroboration’ just a matter of psychology? -/- In this paper, I argue that we can go some way towards addressing this objection by adopting an intersubjective interpretation, of the form advocated by Gillies, with respect to corroboration. I show why intersubjective probabilities are preferable to subjective ones when it comes to decision making in science: why group decisions are liable to be superior to individual ones, given a number of plausible conditions. I then argue that intersubjective corroboration is preferable to intersubjective confirmation of a Bayesian variety, because there is greater opportunity for principled agreement concerning the factors involved in the former. (shrink)

In this paper the strategy for the eliminative reduction of the alethic modalities suggested by John Venn is outlined and it is shown to anticipate certain related contemporary empiricistic and nominalistic projects. Venn attempted to reduce the alethic modalities to probabilities, and thus suggested a promising solution to the nagging issue of the inclusion of modal statements in empiricistic philosophical systems. However, despite the promise that this suggestion held for laying the ‘ghost of modality’ to rest, this general approach, tempered (...) modal eliminativism, is shown to be inadequate for that task.

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Assumptions of stochastic independence are crucial to statistical models in science. But under what circumstances is it reasonable to suppose that two events are independent? When they are not causally or logically connected, so the usual story goes. But scientific models frequently treat causally dependent events as stochastically independent, raising the question whether there are kinds of causal connection that do not undermine stochastic independence. This paper provides one piece of an answer to this question, treating the simple case of (...) two tossed coins with and without a midair collision. (shrink)

THE PAPER EXAMINES WHAT IS MEANT BY ’EVIDENCE’ WHEN IT IS SAID THAT A THEORY IS PROBABLE ON CERTAIN EVIDENCE. IT CONSIDERS WHAT IS THE RELATION BETWEEN A THEORY BEING PROBABLE ON CERTAIN EVIDENCE, A THEORY BEING BELIEVED, AND A THEORY BEING CREDIBLE. IT DISTINGUISHES VARIOUS SENSES OF ’ACCEPT’ IN WHICH SCIENTISTS ARE SAID TO ACCEPT THEORIES, ONLY ONE OF WHICH IS THE SENSE OF ’ACCEPT’ IN WHICH IT IS EQUATED WITH ’BELIEVE’. IT ANALYSES THE LOGICAL RELATIONS BETWEEN A THEORY (...) BEING PROBABLE ON THE EVIDENCE, AND A THEORY BEING ACCEPTED, AND A THEORY BEING ACCEPTABLE, IN THE DIFFERENT SENSES OF ’ACCEPT’. (shrink)

I shall argue that there is no such property of an event as its “probability.” This is why standard interpretations cannot give a sound definition in empirical terms of what “probability” is, and this is why empirical sciences like physics can manage without such a definition. “Probability” is a collective term, the meaning of which varies from context to context: it means different — dimensionless [0, 1]-valued — physical quantities characterising the different particular situations. In other words, probability is a (...) reducible concept, supervening on physical quantities characterising the state of affairs corresponding to the event in question. On the other hand, however, these “probability-like” physical quantities correspond to objective features of the physical world, and are objectively related to measurable quantities like relative frequencies of physical events based on finite samples — no matter whether the world is objectively deterministic or indeterministic. (shrink)

I shall argue that there is no such property of an event as its “probability.” This is why standard interpretations cannot give a sound definition in empirical terms of what “probability” is, and this is why empirical sciences like physics can manage without such a definition. “Probability” is a collective term, the meaning of which varies from context to context: it means different — dimensionless [0, 1]-valued — physical quantities characterising the different particular situations. In other words, probability is a (...) reducible concept, supervening on physical quantities characterising the state of affairs corresponding to the event in question. On the other hand, however, these “probability-like” physical quantities correspond to objective features of the physical world, and are objectively related to measurable quantities like relative frequencies of physical events based on finite samples — no matter whether the world is objectively deterministic or indeterministic. (shrink)