Decisions, Decisions, Decisions: Can Savage Salvage Everettian Probability?

Understand

Critics object that the Everett view cannot make sense of quantum probabilities, in one or both of two ways: either it cannot make sense of probability at all, or it cannot explain why probability should be governed by the Born rule.

• David Deutsch has attempted to meet these objections by appealing to an Everettian version of Savage's rational decision theory.
• Deutsch argues not only that an analogue of classical decision under uncertainty makes sense in an Everett world; but also that under reasonable assumptions, the betting odds of a rational Everettian agent should be constrained by the Born rule.
• Deutsch's proposal has been defended and developed by David Wallace, and in a different form by Hilary Greaves.