Imprecise evidence without imprecise credences

  • Jennifer Rose CarrEmail author


Does rationality require imprecise credences? Many hold that it does: imprecise evidence requires correspondingly imprecise credences. I argue that this is false. The imprecise view faces the same arbitrariness worries that were meant to motivate it in the first place. It faces these worries because it incorporates a certain idealization. But doing away with this idealization effectively collapses the imprecise view into a particular kind of precise view. On this alternative, our attitudes should reflect a kind of normative uncertainty: uncertainty about what to believe. This view refutes the claim that precise credences are inappropriately informative or committal. Some argue that indeterminate evidential support requires imprecise credences; but I argue that indeterminate evidential support instead places indeterminate requirements on credences, and is compatible with the claim that rational credences may always be precise.


Epistemology Bayesianism Imprecise credences Imprecise probabilities 



Thanks to R.A. Briggs, Ryan Doody, Alan Hájek, Richard Holton, Sophie Horowitz, Wolfgang Schwarz, Teddy Seidenfeld, Julia Staffel, Roger White, and audiences at the Australian National University, UCSD, and SLACRR for invaluable feedback.


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© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.University of California, San DiegoLa JollaUSA

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