HPS Centre Seminar

The second HPS Centre seminar of 2019 delivered by Dr Tuomas Tahko ( Bristol) Dependence'

Dr Tuomas Tahko (Department of Philosophy, University of Bristol), will speak on:

Quantum Holism and Mutual Dependence

[This paper is co-authord with Christina Conroy (Morehead State University) & Donnchadh O`Conaill (Université de Fribourg)]

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 they are not absolutely discernible from all other objects or each other; and if they are taken to be individuals, then they violate Leibniz’s Principle of the Identity of Indiscernibles [PII] (French and Redhead 1988, French 1989). In an attempt to maintain the individuality of quantum particles and to salvage the PII, Simon Saunders (2003, 2006) and F.A. Muller (Muller and Saunders 2008) have argued that the PII can be adapted such that it can test for mere weak discernibility, where weakly discernible particles stand in an irreflexive relation to one another.  

Mere weak discernibility and strong non-supervenience have led to a number of different metaphysical developments including what one might call the “historical holistic view” (Shimony 1978; Teller 1986; Healey 1991), relational holism (Teller 1986; Morganti 2009), versions of structural realism (Ladyman 1998; French & Ladyman 2003; Esfeld 2003, 2004; Ladyman & Ross 2007; Esfeld & Lam 2008, 2010; French 2010), and priority monism (Schaffer 2010a; Ismael & Schaffer forthcoming).

We shall outline a metaphysical model suggested by the deep metaphysical connection between entangled particles 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, includes its standing in a specific relation to the other entity. We shall argue this view explains examples of deep metaphysical connection between quantum particles, and may also provide a better account of the metaphysics of these phenomena than does the priority monism recently championed by Jenann Ismael and Jonathan Schaffer.


The research seminar of the Centre for History & Philosophy of Science at the University of Leeds runs fortnightly during term time. Seminars are free and open to all. Tea/coffee will be available from 3:00, but please bring your own cups/mugs.