The most common metaphysical consequence claimed of quantum mechanics is indeterminism. But while the GRW theory is indeterministic, Bohm’s theory is fully deterministic. The many-worlds theory is more interesting. What place could there be for probability in a theory in which every possible outcome of a measurement actually occurs? The options for locating uncertainty within a many-worlds ontology are surveyed, and the arguments that probabilities can be assigned to the worlds are critically assessed. The argument that all of us are immortal according to the many-worlds theory is considered and shown to be mistaken. The consequences of quantum mechanics for free will are shown to be minimal.
Keywords: quantum mechanics, indeterminism, uncertainty, probability, GRW, Bohm, many worlds, immortality, free will