Abstract This paper reconsiders what implications quantum decoherence has for Karen Barad’s agential realism. In contrast with the recent claim of Thomas Everth and Laura Gurney (2022), this paper argues that decoherence supports rather than defeats the holist, relational ontology of agential realism. Indeed, decoherence offers an explanation for how a quantum system can remain entangled and superposed in principle while it nevertheless in practice appears classical to a local observer. Decoherence shows why the appearance of classicality is not an objection to the ontology being in reality that of agential realism, in accordance with Barad’s repeated insistence that we should not mistake principle for practice. Whether users of agential realism in social theory should be encouraged by this is another matter that this paper does not take a stance on. As an ontology, however, agential realism is vindicated.
Abstract This paper reconsiders what implications quantum decoherence has for Karen Barad’s agential realism. In contrast with the recent claim of Thomas Everth and Laura Gurney (2022), this paper argues that decoherence supports rather than defeats the holist, relational ontology of agential realism. Indeed, decoherence offers an explanation for how a quantum system can remain entangled and superposed in principle while it nevertheless in practice appears classical to a local observer. Decoherence shows why the appearance of classicality is not an objection to the ontology being in reality that of agential realism, in accordance with Barad’s repeated insistence that we should not mistake principle for practice. Whether users of agential realism in social theory should be encouraged by this is another matter that this paper does not take a stance on. As an ontology, however, agential realism is vindicated.
K. Barad proposes "agential realism" as a unified approach to natural and social phenomena. The position is inspired by quantum mechanics and in particular the phenomenon of quantum entanglement. Barad also sees similarities between her approach, N. Bohr's view and C. Rovelli's relational quantum mechanics. In our view, agential realism is a kind of ontological correlationism, not a realism. The analogy with the Bohr and Rovelli approaches is only partial. Agential realism is a wrong interpretation of quantum mechanics. It is also unsuitable for social theorizing, for which taking into account the sensitivity of ontology to the context is fundamental. As an alternative, we propose a contextual quantum realism that rejects substantive dualisms (as does Barad), but at the same time accepts the categorical dualism of the real and the ideal. Our approach also allows one to better understand Bohr's position and to correct Rovelli's relational quantum mechanics.
Abstract The last decade has seen an increasing number of references to quantum mechanics in the humanities and social sciences. This development has in particular been driven by Karen Barad’s agential realism: a theoretical framework that, based on Niels Bohr’s interpretation of quantum mechanics, aims to inform social theorizing. In dealing with notions such as agency, power, and embodiment as well as the relation between the material and the discursive level, the influence of agential realism in fields such as feminist science studies and posthumanism has been profound. However, no one has hitherto paused to assess agential realism’s proclaimed quantum mechanical origin including its relation to the writings of Niels Bohr. This is the task taken up here. We find that many of the implications that agential realism allegedly derives from a Bohrian interpretation of quantum mechanics dissent from Bohr’s own views and are in conflict with those of other interpretations of quantum mechanics. Agential realism is at best consistent with quantum mechanics and consequently, it does not capture what quantum mechanics in any strict sense implies for social science or any other domain of inquiry. Agential realism may be interesting and thought provoking from the perspective of social theorizing, but it is neither sanctioned by quantum mechanics nor by Bohr’s authority. This conclusion not only holds for agential realism in particular, it also serves as a general warning against the other attempts to use quantum mechanics in social theorizing.
In this chapter it is argued that the decisive argument against the reducibility of causal relations comes from quantum physics. Bell’s theorem proves that no dynamics based on the local, intrinsic properties of quantum objects can yield the empirical predictions of quantum mechanics. Nonetheless, it is argued that quantum entanglement by no means implies that we have to abandon an ontology of objects in favour of an ontology of structures. All extant proposals for a quantum ontology of matter in spacetime are committed to objects, whose dynamics are determined not by their local, intrinsic properties, but by an holistic property instantiated by all the objects together—a structure that takes all the objects in the universe as its relata. The view set out in this chapter combines ontic structural realism with an ontology of objects that can be conceived as substances.
This study examines the epistemological implications of competinginterpretations of quantum states, focusing on the distinction between epistemicand ontological accounts of the wave function (Harrigan & Spekkens, 2010).Rather than treating interpretative disputes as purely metaphysical, this studyanalyses the extent to which quantum theory constrains, enables or underminesclaims to knowledge about physical reality (van Fraassen, 2008). By situatingthe epistemic–ontological debate within broader discussions of realism,objectivity and scientific explanation, this study argues that quantum theorynecessitates a reconceptualisation of epistemic access to reality (O’Neill,1997). Particular attention is given to the roles of uncertainty, contextuality andobserver-dependence in shaping the epistemic limits of quantum physics (Bohr,1935). The article concludes by proposing a moderate epistemic realism thatpreserves empirical objectivity while acknowledging principled limits onontological transparency (Healey, 2017).
The text points out that one of the main contradictions of quantum realism, which is particularly relevant to the social sciences, is the tension between the existence of an observer-independent reality and the idea that this reality is mediated by the cognitive and interpretative processes of the subject. This contradiction arises from the central role of the observer in phenomena such as the collapse of the wave function and their influence on the construction of reality, which challenges the classical notion of an objective, non-perceptual nature. Moreover, the encounter between social realism and social interpretivism lies in the fact that, in the social sciences, it is also recognized that human interpretations and actions shape social reality, creating a scenario in which absolute objectivity becomes difficult to sustain. These tensions, therefore enrich the epistemological and ontological debate, showing that the contradictions of quantum realism transcend physics and connect deeply with the difficulties and dynamics of the social construction of reality.
As far as classical physics is concerned, it is possible to trace causal relations between physical objects (i.e. particles in this case) back to intrinsic properties of these objects (such as their mass and charge). On this view, causal relations turn out to be internal instead of external relations, supervening on intrinsic properties of the relata (as proposed by Heil and Lowe). However, one can raise doubts about this view already in Newtonian mechanics. The decisive blow to this view comes from quantum physics, with Bell’s theorem proving that no dynamics based on local, intrinsic properties of quantum objects can yield the empirical predictions of quantum mechanics. Nonetheless, quantum entanglement by no means implies that we have to abandon an ontology of objects (i.e. substances such as particles) in favour of an ontology of structures (as claimed by French and Ladyman). Any of the known proposals for a quantum ontology of matter in space-time is committed to objects. However, on any of these proposals, what determines the dynamics of these objects are not local, intrinsic properties, but a global or holistic property instantiated by all the objects together – that is, a structure that takes all the objects in the universe as its relata. The view set out in this paper thus amounts to combining ontic structural realism with an ontology of objects that can be conceived as substances. This suggestion is illustrated by drawing on the ontology of quantum physics worked out by Bohm and Bell. 1.