Question

The following passage discusses competing philosophical frameworks regarding scientific realism.

In the philosophy of science, the debate over scientific realism—the position that our most successful scientific theories accurately describe both the observable and unobservable aspects of the physical world—has long been complicated by the historical phenomenon of theory change. Successive scientific paradigms have frequently discarded the fundamental entities posited by their predecessors. For instance, the transition from classical physics to relativistic and quantum mechanics involved the wholesale rejection of previously indispensable concepts, such as the luminiferous aether and absolute space. Recognizing this pattern of ontological discontinuity, philosopher John Worrall introduced "epistemic structural realism" (ESR), a compromise position attempting to salvage the core realist intuition without ignoring the historical reality of scientific revolutions. Worrall argues that while the proposed unobservable entities (the "nature" of things) change radically between theories, the mathematical equations—the structure—describing the relationships between observable phenomena tend to be preserved across paradigm shifts. Thus, according to Worrall, scientists and philosophers should commit epistemically only to the mathematical structure of our best theories, remaining strictly agnostic about the underlying nature of the entities those structures purportedly describe.

However, Worrall’s formulation has drawn sharp criticism from philosopher James Ladyman, who argues that ESR creates an artificial and untenable dichotomy between structure and nature. Ladyman points out that if we concede, as Worrall does, that we can never attain knowledge of the underlying entities, then postulating the independent existence of these permanently inaccessible entities serves no explanatory purpose. Instead, Ladyman proposes "ontic structural realism" (OSR). Unlike Worrall’s epistemic approach, which merely limits what humans can know about the universe, OSR makes a radical metaphysical claim about what actually exists. Ladyman contends that the universe does not consist of individual objects or entities that enter into relationships; rather, the relationships—the physical and mathematical structures themselves—are all that exists. In OSR, what we traditionally call "particles" are not independent, self-contained "things," but merely intersection points or nodes within a vast relational network.

While Ladyman’s OSR successfully resolves the epistemic gap in Worrall’s theory by eliminating the unknowable entities entirely, it introduces profound conceptual difficulties of its own. Standard metaphysical frameworks are deeply rooted in object-oriented ontology, operating on the intuitive premise that relations require relata—that is, independently existing things to be related. Ladyman’s assertion that relations can exist fundamentally without independently existing objects to anchor them forces a radical, counterintuitive revision of how we conceptualize physical reality. Furthermore, this purely relational view struggles to align smoothly with even the most advanced interpretations of contemporary quantum field theory, where quantum fields, however abstract and non-localized they may be, still appear to function conceptually as foundational, independently existing entities rather than mere structural relations.

Based on the arguments presented in the text, James Ladyman would be most likely to agree with which of the following statements regarding the nature of physical reality?