One of the problems of the many worlds interpretation (MWI) of quantum mechanics is about the ontological status of multiple worlds. In the MWI, the multiple worlds are quasi-classical, and the quasi-classical worlds are considered as emergence and pattern. However, the ontological understanding about the quasi-classical realms remains ambiguous. This article aims to clarify the ontological status of the quasi-classicality in the MWI. In particular, the notion of emergence and pattern has been investigated in the philosophy of science. The investigation about these notions provides a refined ontology of many worlds interpretation.
In this paper I present the common structure of quantum theories with a primitive ontology, and discuss in what sense the classical world emerges from quantum theories as understood in this framework. In addition, I argue that the primitive ontology approach is better at answering this question than the rival wave function ontology approach or any other approach in which the classical world is non-reductively ‘emergent:’ even if the classical limit within this framework needs to be fully developed, the difficulties are technical rather than conceptual, while this is not true for the alternatives.
We present and discuss selected issues related to the problem of representing in a machine-readable way data and knowledge about the quantum level of reality. In particular, we propose a method of creating an ontology for the quantum world. The method uses a mathematical structure of quantum mechanics. We apply the method to obtain a toy ontology corresponding to the Hilbert space formulation of quantum mechanics. We use the terms from the ontology to describe a simple quantum system. We also show how we can use the ontology to create semantic enhancements of scientific publications on quantum mechanics.