I do believe this has no bearing at all with any magical trick capable of making vanishing the other relative worlds, histories, minds, maximal consistent extensions, possibilities ... That seems to me the most preposterous part of Slavnov paper. In 1939 von Neumann still invokes a "magical" role of consciousness in his singling out a "collapsed" reality.
Well sorry, but von Neumann did invoke consciousness in 1932. I was wrong, and it remains an open question for me if von Neumann was hoping that his (modular) Quantum Logic could give light on the conceptual problem of QM.
http://iridia.ulb.ac.be/~marchal/
