An ontological basis for the quantum theory

Gerard ’t Hooft

A sharper formulation is presented for an interpretation of quantum mechanics advocated by the author. We claim that only those quantum theories should be considered for which an ontological basis can be constructed. In terms of this basis, the entire theory can be considered as being deterministic. An example is illustrated: massless, noninteracting fermions are ontological. Subsequently, as an essential element of the deterministic interpretation, we put forward conservation laws concerning the ontological nature of a variable, and the uncertainties concerning the realization of states. Quantum mechanics can then be treated as a device that combines statistics with mechanical, deterministic laws, such that uncertainties are passed on from initial states to final states.

Gregg S. Jaeger

Patrick Jaubert

The causal-set programme proposes that spacetime is, at bottom, a discrete poset whose Lorentzian geometry emerges, endowed with a covariant sequential growth dynamics. It leaves open, however, two points that an ontology must settle: the status of the "becoming" of growth (a computational procedure or a real process?), and the basis of its quantum version (quantum sequential growth, QSG, does not specify the basis of the histories). We show that the theory Time–Actualization (TA) proposes an ontological answer: becoming is posited as real actualization, while the basis is selected by the couplings carried by the causal past, where that monitoring supplies a sharp basis. This identifies an environment within the ontology; it does not derive its coupling content or construct the full quantum dynamics. We present the interface as a consistency bridge, not a refoundation. The emergent geometry and its Hauptvermutung remain inherited, and the dynamical law of actualization remains open. The proposed unification concerns a common process reading of flashes, system actualizations and causal-set growth; their different rates still require an explicit interface.

NORMAN R. CAMPBELL

Richard Dawid, Guilherme Franzmann

Dualities in physics have challenged traditional forms of scientific realism by undermining the idea that theories describe a unique underlying ontology. In this paper, we develop a new perspective on scientific realism that responds to this challenge. We argue that while realist commitment remains appropriate at the level of a theory's full formal structure, ontological commitment should be treated as tied to specific empirical contexts rather than to a fixed, real ontology. Our proposal draws inspiration from Dennett's notion of a "compression algorithm" as a defining criterion of a scientific theory. On this basis, we separate realism from ontological commitment. To clarify the stakes of this distinction, we contrast our approach with common core realism, which locates ontology in the invariant structure shared by dual models. Focusing on dualities in quantum mechanics and string theory, we show how our view accommodates ontological pluralism while preserving a robust form of structural realism.