Morality in a Branching Universe

In most cases, we think that what settles what act it is right to perform is sensitive to what we take the facts about the world to be. But those facts include many controversial metaphysical claims about the world. I argue that depending on what metaphysical model we take to be correct, we will have very different views about what the right actions are. In particular, I argue that if a particular metaphysical model — the branching universe model — is correct, then many of our ethical intuitions are false. We need to think carefully about the relation between ethical and metaphysical intuitions, and ethical and metaphysical theories.