On Some Metaphysical problems of Many Worlds Interpretation of Quantum Mechanics

Christian DE RONDE

Christopher C. Gerry, Kimberley M. Bruno

Standard quantum theory is highly successful in all its applications, from photons and atoms, to semiconductors, superconductors, quarks, and so on. Yet the need to understand what the theory is really trying to tell us about the nature of the world beyond specific predictions forces us into the realm of philosophy, or, as some have dubbed it, quantum metaphysics: the study of the interpretation of quantum mechanics. There is a wide range of opinions regarding the philosophical foundations of quantum mechanics. This chapter focuses on two of the most prominent interpretations: the Copenhagen interpretation, and one alternative interpretation that has been gaining some support in recent years, the many-worlds interpretation (MWI), also known as the many universes interpretation. The central issues of contention are: firstly, that the measurement of some attribute of a quantum system generally involves the probabilistic collapse, or reduction, of the state vector where the probabilistic nature of the process is inherent—that is, not reducible to a more fundamental, deterministic explanation; and, secondly, the problem of bringing a measurement to a completion—a problem generally known as the measurement paradox.

C. Hillis Kaiser

Vladislav Terekhovich

The article continues the debate about whether classical “pure” metaphysics can explain scientific theories or science can generate its own metaphysical concepts. Two camps have emerged in modern analytic philosophy. The “metaphysician” camp defends the metaphysics of science by arguing that the fundamental con­cepts of classical metaphysics can be enriched, illustrated, or justified by exam­ples from scientific theories. The “philosophers of science” camp views this as yet another invasion of metaphysics into their scientific territory. They advocate a scientific or naturalized metaphysics that strictly corresponds to modern scien­tific theories. Since the concept of possible worlds is a key element of main­stream analytic metaphysics, proponents of the metaphysics of science find it natural to appeal to the many-worlds interpretation of quantum theory. In turn, proponents of naturalized metaphysics often use popular metaphysical systems to justify the many-worlds interpretation of quantum mechanics. I will argue that the interpretation originally proposed by H. Everett remains only one of the on­tologies of quantum theory, and attempts by philosophers of science to build a metaphysical construct on its basis encounter serious difficulties.

Jerome Romagosa

Do the worlds described by the Many Worlds Interpretation (MWI)—the most prominent Everettian interpretation of quantum mechanics—genuinely ‘branch’? According to the overlap view, the relationship between branching worlds is described in terms of mereological overlap: worlds share parts with one another through some temporal intervals. In recent years, an alternative known as the divergence view has gained prominence. The divergence view eschews ‘splitting’ and instead holds that Everettian worlds are mereologically disjoint parallel worlds whose histories diverge. I introduce a dilemma for the divergence view to demonstrate that it is metaphysically unsuitable for the MWI.