  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.
