Beyond relationalism in quantum theory: A new indeterminacy-based interpretation of quantum theory

Abstract

The received view in foundations and philosophy of physics holds that if we reject supplementing quantum theory (QT) with certain hidden variables and consider that unitary QT is correct and universal, we should adopt a relationalist interpretation of QT. Relationalist interpretations relativize measurement outcomes to, for example, worlds, systems, agents, or reference frames. It includes the Many-Worlds Interpretation, Relational Quantum Mechanics, and QBism. These interpretations have potential costs connected with their relationalism that make them unattractive. Thus, if there exists a non-relational non-hidden variable universal intepretations of QT, it should be taken seriously. I will present an interpretation of this kind called Environmental Determinacy-based or EnD Quantum Theory (EnDQT), which goes beyond relationalism and the received view. EnDQT circumvents relationalism by constructing an account of indeterminate and determinate values and underlying quantum properties that is not relational while maintaining unitary non-hidden variable universal QT. In situations where a relationalist assumes that measurement outcomes are relativized, such as in the extended Wigner's friend scenarios, according to EnDQT there aren't determinate outcomes but systems with non-relational indeterminate values. In this approach, determinate values arose at some point in time through certain systems and persist due to them via certain interactions represented by certain networks. When there is isolation from the rest of the systems that belong to these networks, such as inside the friend's lab in the extended Wigner's friend scenarios, indeterminate values non-relationally arise inside. I will discuss other independent good reasons for adopting EnDQT, including providing a local causal explanation of Bell correlations and novel empirical posits represented by these networks.