Chance in the Everett interpretation

Abstract

The notion of objective probability or chance, as a physical trait of the world, has proved elusive; the identification of chances with actual frequencies does not succeed. An adequate theory of chance should explain not only the connection of chance with statistics, but with degrees of belief, and more broadly the entire phenomenology of (seemingly) chance events and their measurement. Branching structure in the decoherence-based many worlds theory provides an account of what chance is that satisfies all these desiderata, including the requirement that chance involves uncertainty.

27 pages, 3 figures. This is a lightly edited reprint (with added footnotes and a new appendix) of `Chance in the Everett interpretaiton', in "Many Worlds? Everett, quantum theory and reality", S. Saunders, J. Barrett, A. Kent, and D. Wallace (eds.), Oxford 2010