[T]he Everett interpretation is almost impossible to believe. It postulates that there is vastly more in the world than we are ever aware of. On this interpretation, the world is really in a giant superposition of states that have been evolving in different ways since the beginning of time, and we are experiencing only the smallest substate of the world. It also postulates that my future is not determinate: in a minute’s time, there will be a large number of minds that have an equal claim to count as me. A minute has passed since I wrote the last sentence; who is to know what all those other minds are doing now?
David Chalmers, The Conscious Mind: In Search for a Fundamental Theory, Oxford, 1996, p. 356