Quantum Holism and Essential Dispositions

It is often suggested that at least some entities posited in QM are non-individuals, in the sense that they are numerically distinct entities but there is no fact of the matter as to which entity is which. Such entities are often regarded as holistic, in the sense that they necessarily belong to some larger system (for instance, each member of a pair of entangled electrons necessarily belongs to that system). The metaphysics of holism has been developed in different ways, e.g., relational holism (Teller, Br. J. Philos. Sci. 37:71–81, 1986; Morganti, Philos. Sci. 76:1027–1038, 2009), priority monism (Schaffer, 2010a; Ismael and Schaffer, Synthese 197:4131–4160, 2020) and OSR (Ladyman and Ross, Every thing must go: Metaphysics naturalized. Oxford University Press, Oxford, 2007; Esfeld and Lam, Synthese 160:27–46, 2008; French, 2014).In this paper, we shall outline a metaphysical model of holism which has not yet been developed in detail, in terms of mutual essential dependence. Roughly speaking, two entities are mutually essentially dependent if the essence of each entity, i.e., what that entity is, involves the other entity. This form of dependence can hold between individuals or between non-individuals. It is thus an ideal way to understand the holism of non-individuals in QM.We shall argue that this model of holism applies to a number of topics in QM and particle physics. We shall also argue that this model provides a better account of quantum holism than the priority monism recently championed by Ismael & Schaffer.