Quantum Physics and Realistic Ontology. Historical and Critical Remarks

Gregg S. Jaeger

David Cota

This essay proposes fundamental ontological clarification within contemporary debates on quantum physics: the rigorous distinction between probability as a regime of prediction and the real as material dynamics. Against the widespread view according to which quantum indeterminacy would imply a vague, unstable, or “merely statistical” reality, the text argues that probability belongs to the epistemic plane of knowledge and anticipation, not to the ontological plane of what exists. Quantum physics does not describe an ontologically fluctuating world, but a world whose symbolic access is structurally limited. On this basis, the essay examines the role of Born’s statistical interpretation, decoherence theory, Bell’s theorems, and the Pusey–Barrett–Rudolph result, showing how these impose formal costs on any ontology that conflates formalism and reality. In critical dialogue with QBist, relational, and agential-realist approaches, the text develops a conception of concretion grounded in the notion of mark: the concrete emerges when a material interaction is irreversibly inscribed in a physical support. Stability, far from meaning fixity, is understood as emergent robustness—movement in regime—sufficient to sustain practices, techniques, and historical continuity. The essay concludes by arguing that quantum physics, rather than dissolving the real, demands a more exacting ontology capable of distinguishing precisely between the real, the concrete, and theory.

Valia Allori

In this paper I wish to connect the recent debate in the philosophy of quantum mechanics concerning the nature of the wave-function to the historical debate in the philosophy of science regarding the tenability of scientific realism. Being realist about quantum mechanics is particularly challenging when focusing on the wave-function. According to the wave-function ontology approach, the wave-function is a concrete physical entity. In contrast, according to an alternative viewpoint, namely the primitive ontology approach, the wave-function does not represent physical entities. In this paper, I argue that the primitive ontology approach can naturally be interpreted as an instance of the so-called ‘explanationism’ realism, which has been proposed as a response to the pessimistic-meta induction argument against scientific realism. If my arguments are sound, then one could conclude that: (1) contrarily to what is commonly though, if explanationism realism is a good response to the pessimistic-meta induction argument, it can be straightforwardly extended also to the quantum domain; (2) the primitive ontology approach is in better shape than the wave-function ontology approach in resisting the pessimistic-meta induction argument against scientific realism.

Hilary Putnam

James T. Cushing

In previous chapters we argued that the empirically successful formalism of quantum mechanics supports equally well two mutually incompatible general ontologies: the inherently indeterministic and generally accepted Copenhagen interpretation and Bohm's completely deterministic one. This underdetermination of the interpretation by the formalism is not simply an apparent one of two equivalent theories since there is no way to translate the terms of one of these ontologies into those of the other. This case could be seen as presenting a challenge to the scientific realist who seeks from successful scientific theories a true representation of the world. Furthermore, we suggest that the actual historical competition between these theories and the selection of Copenhagen over Bohm illustrate that such an historically contingent process is not meaningfully distinct from the rational reconstruction and logical judgment of the victorious theory. What is deemed successful and put on offer by the scientific community for the philosopher of science to justify after the fact is itself a contingent and nonunique product. UNDERDETERMINATION The origin of the underdetermination of scientific theories, what we refer to here as the so-called Duhem–Quine thesis, is typically located in Pierre Duhem's The Aim and Structure of Physical Theory (first published in 1906). There Duhem was quite explicit about what he took to be the basis for judging whether or not a given physical theory is acceptable.