The Natural Criticality Hypothesis of Subjective Time — A Neurodynamic Formalization via Action Readiness Density r(t) —

A unified neurological principle of subjective time has yet to be established. This

study proposes a neurodynamic hypothesis that treats the brain as a self-organized

critical system (SOC) and defines subjective time as the inverse of action readiness

density (r(t))—an operational variable representing the local neural update rate,

defined as the multiplicative combination of cortical gain modulation by the locus

coeruleus–norepinephrine system (LC–NE), interoceptive precision in the anterior

insula, and predictive structural coherence. Subjective time τ(t) is given by τ(t) =

1/r(t), and healthy fluctuations of r(t) are hypothesized to follow 1/f noise near the

critical point (Edge of Chaos). Crucially, r(t) is not a purely endogenous variable: its

lower bound is supported by external information such as predictability, safe bases,

rhythm, the presence of others, and narrative, making it indirectly manipulable.

This hypothesis further incorporates the extension that subjective time is not

generated along a single axis but in parallel across multiple contexts. The stability

of the sense of self is defined as the degree of convergence among these multiple time

axes, and their divergence is proposed to manifest as depersonalization, dissociation,

and burnout precursor states.

This framework offers a unified account of phenomena as diverse as depression,

anxiety, freezing, burnout, flow, being moved, tears, laughter, anticipatory reward,

and safe base—each re-described as a particular configuration of r(t)’s level, sta-

bility, retention, release, or re-regulation. The model does not aim to explain the

qualia of subjective time, but to describe its structure and dynamics and to establish

predictive and interventional operability.