Abstract This paper offers a relational reinterpretation of the ontological status of fundamental physical quantities from the unique perspective of engineering constraint analysis. Moving beyond traditional substantivalism, it posits that concepts such as energy, mass, frequency, and wavelength are not independently existing entities but rather interlocked nodes collectively defined by the intrinsic constraint network constituted by fundamental laws like E = mc², E =, and c =. Within this framework, the speed of light c and the reduced Planck constant are not mysterious empirical inputs but endogenous structural "exchange rates" necessary to maintain the network's self-consistency (ensuring Lorentz invariance and quantum coherence, respectively). This model not only philosophically resonates with the core tenet of Ontic Structural Realism (OSR) —that "relations precede relata"—but also provides a more foundational conceptual underpinning for Relational Quantum Mechanics (RQM). This relational perspective offers a new philosophical lens for understanding modern metrology. The paper argues that the 2019 revision of the International System of Units (SI) represents an outstanding operational reverse-engineering of this intrinsic relational network: by anchoring the most stable quantum frequency node (the cesium hyperfine transition) as the benchmark and utilizing the network's inherent structural relations (such as c), human civilization has effectively "decoded" and operatively accessed this network, thereby defining the second and the meter. Thus, measurement is elevated from mere social convention to a systematic reading of the inherent relational structure of nature. This paper does not propose a new physical theory but demonstrates a cross-paradigm methodological migration: applying the "debugging" and "constraint analysis" mindset refined in extreme engineering practice to clarify conceptual issues in the foundations of physics. This work provides a novel, rigorous, and operational interpretative framework for understanding the relational nature of physical reality. Relational Ontology and the Constraint Network This relational ontology provides a powerful lens for reinterpreting modern metrology. The 2019 revision of the International System of Units (SI) is revealed as a masterful exercise in operational reverse engineering: by fixing the most stable quantum frequency (caesium atomic transition) as a reference node and leveraging the network's inherent relation c, human civilization has effectively "decoded" and operationally interfaced with this a priori physical structure, thereby defining the second and the metre. Measurement is thus elevated from mere convention to the reading of nature's own relational blueprint, with the Planck units marking the ultimate resolution limit of any such decoding under current physical laws. Conclusion and Contribution Therefore, this paper is not a new physical theory, but a detailed report on a cross-paradigm thought experiment. It demonstrates how a methodology forged at the extreme forefront of engineering (debugging complex systems) can be successfully transferred to clarify profound conceptual issues in physics and philosophy of science, offering a novel, rigorous, and operational perspective on the relational nature of physical reality. Keywords relational ontology; constraint network; natural units; philosophy of metrology; International System of Units (SI) ; cross-paradigm thinking; debugging methodology; Planck units; measurability limit
Shicong Zhou (Sat,) studied this question.