Philosophy of Physics Seminar

Abstract: One hundred years ago, the 23 year old Frank Ramsey presented a paper to the Cambridge Moral Sciences Club in which he presented a subjective account of probability; solved the problem of how to measure degrees of belief; and outlined a model of subjective expected utility. The Polish mathematician Janina Hosiasson and the Italian Bruno de Finetti would soon come to similar results, seemingly independently of Ramsey. It was an important idea whose time had come. It now underpins contemporary economics and Bayesian statistics, as well as much of psychology, medicine, and other social and physical sciences.

In this paper, I show that it was an idea that could only have come about with pragmatism, something all three founders of subjective probability theory recognized. I note that there are two kinds of pragmatists, one radically subjectivist and the other more objectivist but still focused on the human element in rationality. I argue that Ramsey's objectivist pragmatism is the way to go; that he was not open to a challenge made by Hosiasson; and that de Finetti took a wrong turn. I then suggest that contemporary Bayesians should follow Ramsey when it comes to the issue of whether we can and ought to assess our priors.

Registration: If you do not hold a university card, please contact the seminar convenor or admin@philosophy.ox.ac.uk at least two working days before a seminar to register your attendance.

_{Philosophy of Physics Seminar Convenor: Chris Timpson  | Philosophy of Physics Group Website}