  In a recent result, Frauchiger and Renner argue that if quantum theory
accurately describes complex systems like observers who perform measurements,
then "we are forced to give up the view that there is one single reality."
Following a review of the Frauchiger-Renner argument, I argue that quantum
mechanics should be understood probabilistically, as a new sort of non-Boolean
probability theory, rather than representationally, as a theory about the
elementary constituents of the physical world and how these elements evolve
dynamically over time. I show that this way of understanding quantum mechanics
is not in conflict with a consistent "single-world" interpretation of the
theory.
