‘Two Dogmas’ Redux

I revisit the paper ‘Two dogmas about quantum mechanics,’ co-authored with Itamar Pitowsky, in which we outlined an information-theoretic interpretation of quantum mechanics as an alternative to the Everett interpretation. Following the analysis by Frauchiger and Renner of ‘encapsulated’ measurements (where a super-observer, with unrestricted ability to measure any arbitrary observable of a complex quantum system, measures the memory of an observer system after that system measures the spin of a qubit), I show that the Everett interpretation leads to modal contradictions. In this sense, the Everett interpretation is inconsistent.