, Volume 21, Issue 1, pp 193-196
Date: 06 Apr 2011

Objective Bayesianism defended?

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access
This is an excerpt from the content

Objective Bayesianism is the view that an agent’s degrees of belief should satisfy three constraints in order to be rational. First, they should satisfy the probability calculus. Second, they should be sensitive to the agent’s evidence (e.g., of physical chances, frequencies or correlations). Third, and finally, they should otherwise be maximally non-committal (or ‘equivocate between basic outcomes’ (iii)). Williamson calls these the probability, calibration and equivocation norms.

To illustrate, imagine that an agent knows (or believes) of a die only that it is a regular tetrahedron, with sides labelled ‘i’, ‘ii’, ‘iii’ and ‘iv’.

Such ‘knows only’ (or ‘believes only’) scenarios, common in the literature on decision theory, are more troublesome than they first appear. It is difficult to specify what precisely we are to assume that the agent knows (or believes) in any given case. (Here, for example, I want you to assume that the agent isn’t familiar with rolls of similar objects, e.g., ot