Does it Make Sense to Speak of Self-Locating Uncertainty in the Universal Wave Function? Remarks on Sebens and Carroll
Following a proposal of Vaidman (Int Stud Philos Sci 12:245–261, 1998) (in: Zalta EN (ed) The Stanford encyclopaedia of philosophy, 2014) (in: Ben-Menahem Y, Hemmo M (ed) The probable and the improbable: understanding probability in physics, essays in memory of Itamar Pitowsky, 2011), Sebens and Carroll (Quantum theory: a two-time success story 2014), (arXiv preprint arXiv:1405.75772014) have argued that in Everettian (i.e. purely unitary) quantum theory, observers are uncertain, before they complete their observation, about which Everettian branch they are on. They argue further that this solves the problem of making sense of probabilities within Everettian quantum theory, even though the theory itself is deterministic. We note some problems with these arguments.