Traditional physical ontology relies on the assumption of observer-independence, regarding a physical state as an intrinsic property that exists prior to measurement, with observation acting merely as a passive retrieval of pre-existing facts. This paper challenges this view and articulates a relational paradigm of physics: at fundamental levels, physical states are not absolute inherent attributes, but structural outputs generated through mutual interactions among the system, the environment, and the observational framework. By re-evaluating quantum collapse, quantum decoherence, and relational quantum mechanics, this study demonstrates how the choice of measurement basis and environmental interactions selectively determine pointer states and establish classicuality. Furthermore, the relational character of physical states is corroborated in macroscopic domains, including the dependency of thermodynamic entropy on coarse-graining and the reference-frame relativity of spatiotemporal states in general relativity and the Unruh effect. By reframing physics around interaction boundaries and information exchange, this paper establishes a relational realism that transcends both rigid objective realism and subjective idealism, offering insight into foundational problems in quantum gravity and quantum cosmology without appealing to external observers.
Traditional physical ontology relies on the assumption of observer-independence, regarding a physical state as an intrinsic property that exists prior to measurement, with observation acting merely as a passive retrieval of pre-existing facts. This paper challenges this view and articulates a relational paradigm of physics: at fundamental levels, physical states are not absolute inherent attributes, but structural outputs generated through mutual interactions among the system, the environment, and the observational framework. By re-evaluating quantum collapse, quantum decoherence, and relational quantum mechanics, this study demonstrates how the choice of measurement basis and environmental interactions selectively determine pointer states and establish classicuality. Furthermore, the relational character of physical states is corroborated in macroscopic domains, including the dependency of thermodynamic entropy on coarse-graining and the reference-frame relativity of spatiotemporal states in general relativity and the Unruh effect. By reframing physics around interaction boundaries and information exchange, this paper establishes a relational realism that transcends both rigid objective realism and subjective idealism, offering insight into foundational problems in quantum gravity and quantum cosmology without appealing to external observers.
Quantum mechanics reveals that physical quantities and informational states are not absolute but relational, depending on the context of interaction between systems. While classical physics already contained relational elements—most clearly in Galilean relativity and Einstein’s relational spacetime—the quantum domain extends relationality to physical properties and facts themselves. In this paper, I develop an info-computational perspective on relational quantum mechanics (RQM), conceiving observers as informational agents embedded within physical processes. Quantum states are understood as constraints on possible interactions rather than intrinsic attributes of isolated systems. I review key relational, perspectival, and information-theoretic approaches—including QBism, perspectival quantum realism, reference-frame–dependent observables, categorical quantum mechanics, and graph-based formalisms—and argue that they converge on a view of physics grounded in relations and information flow. Relational objectivity emerges through inter-agent translation rules rather than observer independence, providing a unified framework for understanding quantum measurement, inter-observer agreement, and physical ontology.
Quantum mechanics has transformed our understanding of reality, yet deep philosophical puzzles remain unresolved. Is there a consistent way to describe quantum measurement, the emergence of space and time, and the role of observers within one coherent ontology? This paper introduces Relational Quantum Dynamics (RQD), an interpretation that places relationships and information—not isolated objects—at the foundation of physics. Unlike traditional views, such as the Copenhagen interpretation, Everett’s many-worlds theory, or hidden-variable approaches, RQD denies a single observer-independent reality, instead proposing that facts only become definite within specific observational contexts. It explicitly addresses foundational no-go results, including Bell’s theorem, the Kochen–Specker theorem, and the Frauchiger–Renner paradox, by replacing absolute facts with relational, context-dependent truths. RQD rests on five interlocking principles: (1) quantum states are contextual and observer-relative, (2) time emerges from quantum interactions rather than existing as an external parameter, (3) space is constructed from patterns of quantum entanglement, (4) observers emerge as systems with highly integrated information, and (5) classical reality appears through quantum decoherence without special wavefunction collapse. Philosophically, RQD aligns with ontic structural realism, proposing that the fundamental ontology of the universe consists entirely of informational relations. It avoids collapsing into relativism or solipsism by ensuring intersubjective agreement through physical interactions. Ultimately, RQD may offer a unified picture in which quantum mechanics, spacetime, and observers are no longer separate domains but aspects of one interconnected informational web.
Quantum mechanics has transformed our understanding of reality, yet deep philosophical puzzles remain unresolved. Is there a consistent way to describe quantum measurement, the emergence of space and time, and the role of observers within one coherent ontology? This paper introduces Relational Quantum Dynamics (RQD), an interpretation that places relationships and information, not isolated objects, at the foundation of physics. Unlike traditional views, such as the Copenhagen interpretation, Everett's many-worlds theory, or hidden-variable approaches, RQD denies a single observer-independent reality, instead proposing that facts only become definite within specific observational contexts. It explicitly addresses foundational no-go results, including Bell's theorem, the Kochen-Specker theorem, and the Frauchiger-Renner paradox, by replacing absolute facts with relational, context-dependent truths. RQD rests on five interlocking principles: (1) quantum states are contextual and observer-relative, (2) time emerges from quantum interactions rather than existing as an external parameter, (3) space is constructed from patterns of quantum entanglement, (4) observers emerge as systems with highly integrated information, and (5) classical reality appears through quantum decoherence without special wavefunction collapse. Philosophically, RQD aligns with ontic structural realism, proposing that the fundamental ontology of the universe consists entirely of informational relations. It avoids collapsing into relativism or solipsism by ensuring intersubjective agreement through physical interactions. Ultimately, RQD may offer a unified picture in which quantum mechanics, spacetime, and observers are no longer separate domains but aspects of one interconnected informational web.
This study proposes a counterfactual history and theoretical model of physics: assuming that Albert Einstein in the early 20th century had not prioritized the spacetime variability hypotheses of special and general relativity, but instead adopted the axiom that "an observer possesses no independent physical identity," thereby establishing "Relational Physicality." Within this framework, measurement outcomes are strictly defined as the state of interaction between the observer and the measured system, rather than intrinsic properties inherent to the measured system itself. This paper demonstrates that when the "observer" is demoted to an inseparable part of a physical system, the spatiotemporal relativity of special relativity and the measurement collapse problem of quantum mechanics can be consistently explained within a unified logical scheme. Physical facts are no longer objective realities independent of observational relations, but rather manifest representations of relational states among physical entities. This theoretical paradigm not only reconstructs the evolutionary path from classical to modern physics, but also provides a novel philosophical and physical foundation for unifying relativity and quantum mechanics.
We argue that quantum randomness is a logical necessity arising from the nature of intrinsically relational properties—properties lacking definite states outside specific contexts of causal interaction. This motivates Relational Actualism (RAQM), an ontological framework classifying physical properties as invariant, classical, or intrinsically relational. RAQMgrounds wave function actualization in physical interaction rather than observer-relative facts. The actualization criterion is physically grounded and mathematically precise: an interaction constitutes an actualization event when it produces an irreversible increase in the entanglement entropy of the system with its asymptotic environment, generating a robust, redundant causal record. In weakly coupled QFT, a sufficient condition is the exchange of a real, on-shell excitation (pμ pμ = m2c2). This criterion is basis-independent, nonperturbative, and requires no new fundamental constants. To reconcile a globally consistent wave function with special relativity, the Tomonaga-Schwinger equation establishes a foliation-independent global update mechanism. We derive a consistency condition demonstrating that RAQM’s actualization map preserves identical observable statistics at spacelike-separated points regardless of hypersurface choice—a derived result, not a postulate—strictly forbidding superluminal signaling via algebraic microcausality. The no-signaling result applies rigorously to the non-selective (outcome-averaged) actualization map; conditioned branches are treated explicitly. Three specific, discriminating empirical predictions are stated: a finite actualization propagation velocity bounded by the Lieb-Robinson speed, an environment-dependent transition duration scaling as ℏ/ΔEenv, and a sharp reversibility threshold at the actualization criterion. RAQM is distinguished from Relational Quantum Mechanics (which relativizes facts), dynamical collapse models (which ground collapse in stochastic gravitational thresholds rather than causal interaction), decoherence-only models (which leave the outcome problem open), and Everettian Many-Worlds (which denies definite events). Classical behavior emerges dynamically when continuous actualization events eliminate all unconstrained degrees of freedom. The companion papers RAGC and RACI extend these results to gravity, cosmology, and biological complexity; RAHC [Sandeman, 2026e] extends the framework further to the emergence of agentic intelligence, formalizing the recursive coarse-graining hierarchy that generates successive levels of causal closure from the microscopic DAG; key theorems in those papers have been formally verified in Lean 4/Mathlib. A second Lean 4 file (RA_AQFT_Proofs_v10.lean) formalises the finite-dimensional AQFT proof program and proves the frame-independence and Rindler stationarity theorems; see the note on formal verification in the companion paper RAGC [Sandeman, 2026b].
Every physical theory is constructed from observations performed within a physical frame, and this frame enters the theory at a level antecedent to its equations — in the categorical structure through which observations are organized into a formalism. This is a structural condition on physical theory as such, not a hypothesis about any particular physical phenomenon; its character is analogous to the principle of general covariance, which constrains the form of physical laws without predicting the behavior of any specific system. The condition has a precise formal consequence in the geometric setting: for any non-invariant tensor field under a frame- transformation group, the components specified in any single frame are insufficient to determine the underlying geometric object without explicit specification of the frame. This consequence has been articulated four times in the foundations of physics — in the tensor reformulation of electrodynamics, in the relativity of simultaneity, in the unification of energy and momentum, and in the geometric unification of space and time — each time by identifying a frame-dependence carried implicitly in the prevailing formalism and absorbing it into a geometric object across the class of frames. Rovelli’s (1996) relational quantum mechanics is the most explicit contempo- rary articulation of the structural condition: the frame is the physical system to which a quantum state is referred, and the relational structure is exhibited directly at the level of the measurement interaction. The condition implies that relationality must arise wherever current physics is examined at the level of its foundations — not because relationality is a fundamental feature of the physics under description, but because it is a necessary feature of any theory constructed from observations performed within physical frames, and open foundational problems are most plausibly resolved by making implicit frame-dependences explicit rather than by eliminating them.