Starting from the most primitive perceptual experience of human beings, this paper establishes a physical measurement system without any external absolute benchmark via pure logical deduction. We demonstrate that time serves as the inevitable logical prerequisite for describing physical evolutions and the foundational definition of all physical quantities; measurement benchmarks originate intrinsically from material distributions and are modulated by ambient mass density. The self-consistency constraint of locally variable benchmarks uniquely yields the time-field flux conservation equation \nabla \cdot (\gamma \nabla \gamma)=0. Known as Time Field Theory (TFT), this framework recovers all measurable predictions of general relativity and resolves the ontological problems caused by spacetime substantivalism, furnishing a unified metrological epistemology for both classical physics and quantum mechanics. This paper lays the philosophical foundation of TFT; follow-up derivations including gravitational equations, observational tests, gravitational wave analysis, cosmological modeling and canonical quantization are elaborated in the author’s serial Zenodo publications, with falsifiable experimental predictions provided therein.