Instrumentalization of Scientific Realism

Updated 10 April 2026

Instrumentalization of Scientific Realism is defined by repurposing realist language for practical, heuristic, and sociological purposes rather than adhering to strict truth claims.
In quantum foundations, wave function realism is endorsed for its unification and locality virtues, prioritizing predictive accuracy over a literal ontological commitment.
Across disciplines like logic and metaphysics, this trend shifts the focus from truth-based realism to frameworks that value empirical adequacy and explanatory unity.

The instrumentalization of scientific realism denotes a methodological trend and philosophical critique wherein the language, rhetoric, and ontological claims of scientific realism are harnessed to serve pragmatic, heuristic, or sociological purposes, rather than constituting a substantive commitment to the truth of scientific theories or the existence of their ontologies. This process, especially pronounced in the philosophy of quantum mechanics and logic, exposes tensions between traditional truth-anchored realism and its contemporary deployments, revealing forms of “realism” that function, in practice, as sophisticated instrumentalism.

1. Ontological and Meta-Ontological Dimensions of Scientific Realism

Scientific realism is a two-level doctrine. Ontologically (the internal level), it posits that the entities, structures, and processes postulated by our best scientific theories—such as electrons, fields, or wave functions—exist, with ontological questions framed as "What exists?" within a theory-relative language. Meta-ontologically (the external level), realism claims that the theoretical framework itself is (approximately) true, and that its ontology corresponds to the world's actual structure; meta-ontological questions probe whether objective answers exist to ontological questions, theory-independently. Without the meta-ontological layer (i.e., the claim that one's best framework or theory is true), scientific realism is deprived of its core connection to truth and loses its foundational claim that science systematically tracks what there is (Arroyo et al., 29 Jul 2025).

Instrumentalization arises when purportedly realist stances adopt realist vocabulary—asserting the reality of entities or the truth of a theory—but ground these assertions not in alethic (truth-conducive) evidence but in pragmatic, heuristic, or convergently useful virtues such as simplicity, locality, or explanatory fruitfulness, while deliberately withholding commitment to the framework’s actual truth (Arroyo et al., 29 Jul 2025).

2. Instrumentalization in Quantum Foundations: Wave Function Realism

Wave function realism (WFR), especially in its high-dimensional formulation (WFR^HD), exemplifies the instrumentalization of realism in contemporary quantum foundations. WFR^HD asserts that the quantum wave function $\psi$ is a real physical field defined on a high-dimensional configuration space, as encoded in the equation

$i\hbar\, \frac{\partial \psi(q_1,\ldots,q_N, t)}{\partial t} = \widehat{H} \psi(q_1,\ldots,q_N, t)$

where $q_i \in \mathbb{R}^3$ and $\psi$ lives on $3N$-dimensional configuration space or, in quantum field terms, on Fock space as $\Psi[\phi(x), t]$ . In the canonical exposition, the indispensability of $\psi$ for any putative solution to the measurement problem underwrites its ontological status.

However, WFR^HD, as articulated by proponents like Ney, concedes that foundational underdetermination in quantum theory prohibits any demonstration that the high-dimensional framework is uniquely correct. Instead, WFR^HD is defended on pragmatic grounds: only this ontology satisfies certain unification, locality, and separability virtues, particularly in offering a uniform account of entanglement and a categorization of separable versus non-separable states (Arroyo et al., 29 Jul 2025). Simplicity, locality, and intuitive appeal are invoked as criteria for preferring the WFR^HD framework, but not as reasons to accept its literal truth: meta-ontological commitment is expressly suspended.

This approach severs WFR^HD from the alethic core of scientific realism. It deploys the language of realism—asserting that wave functions are real fields—while justifying this ontology on non-truth-conducive pragmatic criteria, making WFR^HD indistinguishable in practice from constructive empiricism or empiricist "acceptance" of theories for empirical adequacy alone (Arroyo et al., 29 Jul 2025).

3. Modalities of Instrumentalized Realism Across Disciplines

Instrumentalization of realism is not limited to quantum foundations; it recurs in logic and the broader metaphysics of science.

Anti-exceptionalism about logic (AEL) illustrates this mechanism: AEL borrows from scientific methodology and realism the abductive and predictive techniques for theory choice, presupposing that logic, like science, aims at discovering the "one true logic" that describes a mind-independent structure. Yet this importation is a historical and sociological contingency, not a metaphilosophical necessity—alternative antirealist backgrounds (e.g., constructive empiricism) could equally serve as the basis for logical theory choice, focusing on empirical adequacy rather than truth (Arenhart et al., 6 Jul 2025). Once the sociological contingency is exposed, it becomes clear that realist language in logic often functions as a heuristic for organizing research agendas, rather than as a robust ontological doctrine.

The pattern generalizes: Across fields, "realism" becomes a flexible label guiding preferred frameworks, justified by their mathematical virtues, explanatory power, or systematic fruitfulness, but without substantive commitment to their veracity (Arenhart et al., 6 Jul 2025).

4. Underdetermination, Explanatory Pluralism, and Projective Realism

Contemporary accounts of scientific explanation, particularly those deploying the formalism of projections, further reveal the role of instrumentalized realism. Projections $\pi: S \to D$ map complex underlying state spaces $S$ —e.g., molecular microstates, economic agents, logical systems—onto structured descriptive spaces $D$ . Each projection identifies compatibility classes where suppressed details become irrelevant to the invariants visible at that level (e.g., the gas law $i\hbar\, \frac{\partial \psi(q_1,\ldots,q_N, t)}{\partial t} = \widehat{H} \psi(q_1,\ldots,q_N, t)$ 0 as an invariant independent of molecular details).

Legitimacy criteria for adopting a projection are empirical adequacy (the projection accounts for all known regularities in its domain) and ontological consonance (the projection’s substrate interpretation is consistent with established ontologies from adjacent domains) (Sticker, 17 Mar 2026). Multiple projections—potentially incompatible, non-embedable, and level-specific—can coexist, reflecting the intractable underdetermination of the underlying structure by empirical data. Here, realism is "instrumentalized" into a commitment not to the truth of any individual projection's substrate-ontology, but to the reality of the invariants and structures preserved across levels and projections.

Progress, on this model, is judged by whether a successor projection better satisfies empirical adequacy and ontological consonance and embeds the invariants of its predecessor, not by securing a final truth about ultimate ontology (Sticker, 17 Mar 2026). Such structural accounts reconcile realism with explanatory pluralism but risk collapsing any strong ontological commitment into a pragmatic regulatory ideal.

5. Collapse of Realist Commitment and Critiques in Quantum Theory

In the quantum context, the instrumental deployment of realism becomes especially transparent. Empirical practice is grounded in predictive accuracy and operational success, not ontological interpretation. Interpretations of quantum mechanics (collapse models, Everettian, Bohmian, QBist, etc.) proliferate without empirical discrimination. Realist commitment, unable to adjudicate among empirically equivalent options, recedes to personal, aesthetic, or heuristic preferences. This process results in a progressive dilution of realism—to internal or pragmatic forms (Putnam), selective or structural realism, or mere “approximate truth”—none of which fulfill the traditional realist aspiration to a mind-independent ontology (Arroyo et al., 2022).

Consequently, ontological interpretations function largely as “fictive tools” or “heuristic stories,” supporting the empirical apparatus but ultimately dispensable for the scientific enterprise. This undermines the practical distinction between realism and antirealism and exposes the essentially instrumental function of "realism" in much of quantum foundational discourse (Arroyo et al., 2022).

6. Alternatives and Countercurrents: Participatory Realism

Participatory realism, exemplified by QBism and interpretations inspired by Wheeler's "law without law," resists pure instrumentalization by reframing realism itself around the irreducible role of agents and first-person perspectives in the quantum formalism (Fuchs, 2016). Here the Born rule is interpreted as a normative constraint on agents’ probabilities,

$i\hbar\, \frac{\partial \psi(q_1,\ldots,q_N, t)}{\partial t} = \widehat{H} \psi(q_1,\ldots,q_N, t)$ 1

where the agent’s probability assignments are subject to universal consistency constraints. In participatory realism, reality is co-constructed through agent–system interaction, with the formal structure of theory encoding objective features of the world that transcend mere instrumental prediction.

Thus, participatory realism eschews both traditional objectivist realism and simple instrumentalism, asserting a form of realism anchored in normative, shared structure—distinct from the instrumentalized stances critiqued elsewhere. This provides a distinct response to the trend of instrumentalization, seeking to restore substantive content to realism while acknowledging the limitations of third-person, impersonal accounts (Fuchs, 2016).

Summary Table: Forms of Instrumentalization

Domain	Instrumentalized Realism Manifestation	Key Mechanism
Quantum Mechanics	Pragmatic defense of ontologies (WFR^HD), proliferation of empirically equivalent interpretations	Suspension of meta-ontological commitment; focus on practical virtues
Logic	Methodological realism in anti-exceptionalism	Import of scientific methodology without ontological commitment
General Science	Plural projections and explanatory pluralism	Normative criteria for adequacy/consonance replace strong realism

Instrumentalization of scientific realism denotes the decoupling of realist rhetoric and ontological assertion from truth-conducive reasoning within scientific practice and philosophy. It surfaces in quantum foundations, logic, and the philosophy of scientific explanation as a slide from traditional, truth-anchored realism to weaker stances where pragmatic, heuristic, and sociological virtues drive theoretical preference, often rendering the distinction between realism and antirealism moot. Counterexamples such as participatory realism offer alternative reconceptualizations, but the general trend marks a transformation in the philosophy of science, necessitating new frameworks for intellectual commitment, progress, and ontology (Arroyo et al., 29 Jul 2025, Arenhart et al., 6 Jul 2025, Sticker, 17 Mar 2026, Arroyo et al., 2022, Fuchs, 2016).