Time as Primary Substrate: A Unified Framework

This paper presents a unified framework in two parts. Part I establishes, on the basis of established general relativity and FLRW cosmology, that the cosmic-average rate of proper time dτ/dt increases monotonically as the universe expands and the mean gravitational potential weakens. This kinematic result is supported by observational evidence that time ran approximately five times more slowly in the early universe than today. Part I also challenges the assumption of universal temporal passage — the residual Newtonian presumption that time flows uniformly everywhere — and introduces an exploratory conjecture that the subjective acceleration of time perception in aging humans may carry a weak cosmological component. Part II provides a causal mechanism for the result of Part I: the Big Bang is proposed to have been a phase transition in which a primordial temporal field of high energy density began condensing into the gravitational and matter fields of the observable universe. The residual uncondensed energy density of this field is identified with the cosmological constant Λ, offering a natural resolution of the cosmological constant problem that requires no fine-tuning: Λ is small because condensation is nearly complete after 13.8 billion years. Three testable predictions follow: a deviation of the dark energy equation of state from w = −1, a secular decrease in effective Λ, and the absence of a vacuum decay catastrophe. Taken together, the two parts constitute a single argument: time is not the backdrop of physics but its primary physical substrate.