In Defence of Objective Bayesianism

How strongly should you believe the various propositions that you can express?

That is the key question facing Bayesian epistemology. Subjective Bayesians hold that it is largely (though not entirely) up to the agent as to which degrees of belief to adopt. Objective Bayesians, on the other hand, maintain that appropriate degrees of belief are largely (though not entirely) determined by the agent's evidence. This book states and defends a version of objective Bayesian epistemology. According to this version, objective Bayesianism is characterized by three norms:

DT Probability - degrees of belief should be probabilities
DT Calibration - they should be calibrated with evidence
DT Equivocation - they should otherwise equivocate between basic outcomes

Objective Bayesianism has been challenged on a number of different fronts. For example, some claim it is poorly motivated, or fails to handle qualitative evidence, or yields counter-intuitive degrees of belief after updating, or suffers from a failure to learn from experience. It has also been accused of being computationally intractable, susceptible to paradox, language dependent, and of not being objective enough.

Especially suitable for graduates or researchers in philosophy of science, foundations of statistics and artificial intelligence, the book argues that these criticisms can be met and that objective Bayesianism is a promising theory with an exciting agenda for further research.

Jon Williamson is Professor of Reasoning, Inference and Scientific Method in the Philosophy Department at the University of Kent. He works on causality, probability, logic and applications of formal reasoning within science, mathematics and artificial intelligence. Jon currently heads the philosophy department and is a director of the Centre for Reasoning at the University of Kent. He runs the Reasoning Club, a network of research centers, and edits The Reasoner, a monthly gazette on research in this area.