What is a quantal reality?

          @misc{ scivideos_PIRSA:09060014,
            doi = {10.48660/09060014},
            url = {https://pirsa.org/09060014},
            author = {Sorkin, Rafael},
            keywords = {Quantum Information, Quantum Foundations},
            language = {en},
            title = {What is a quantal reality?},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2009},
            month = {jun},
            note = {PIRSA:09060014 see, \url{https://scivideos.org/pirsa/09060014}}
          }
          

Abstract

I will rephrase the question, "What is a quantal reality?" as "What is a quantal history?" (the word history having here the same meaning as in the phrase sum-over-histories). The answer I will propose modifies the rules of logical inference in order to resolve a contradiction between the idea of reality as a single history and the principle that events of zero measure cannot happen (the Kochen-Specker paradox being a classic expression of this contradiction). The so-called measurement problem is then solved if macroscopic events satisfy classical logic, and this can in principle be decided by a calculation. The resulting conception of reality involves neither multiple worlds nor external observers. It is therefore suitable for quantum gravity in general and causal sets in particular.