Reflections on Sleeping Beauty

Abstract

Adam Elga (2000) presents a puzzle, the ‘Sleeping Beauty’ puzzle, which concerns the updating of belief when a person, Sleeping Beauty, finds something out about her temporal location in the world. He claims that in such cases, even though she apparently only learned something about her temporal location in the world, and nothing about the world per se, she should nonetheless change her degrees of belief in what the world is like. And Elga claims that in so doing she will violate Bas van Fraassen’s ‘Reflection Principle’. (See van Fraassen 1984 and van Fraassen 1995.) After presenting Elga’s argument I will present an alternative argument which has as its conclusion that Sleeping Beauty should not change her degrees of belief. I will then argue that neither of these arguments by itself is compelling, that one should distinguish degrees of belief from acceptable betting odds, and that some of the time Sleeping Beauty should not have