  Following a proposal of Vaidman, Sebens and Carroll 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.
