The Principle of Stationary Evolution: A Variational Foundation for an Evolution-Based Description of Physical Time

The principle of stationary action occupies a central position in modern physics by determining the dynamics of classical and relativistic systems. In this work, a more fundamental variational principle is proposed in which the primary physical quantity is not time but the local rate of physical evolution. The accumulated evolution experienced by a physicalsystem is treated as the operational quantity measured by physical clocks, while time is interpreted as an emergent parameter constructed from accumulated evolution.A scalar evolution field, referred to as Evoltropy, is introduced to characterize the normalized local rate of physical evolution throughout spacetime. Based on this field, the Principle of Stationary Evolution is proposed, stating that the physically realized trajectory between two events renders the accumulated evolution stationary. A covariant particle action isconstructed from this principle, and its variational formulation provides the foundation for deriving the equations of motion within the proposed framework.The principle reproduces the experimentally verified relativistic relation between velocity and clock rates while providing an alternative interpretation in which clocks measure accumulated evolution rather than the flow of an independently existing temporal dimension.The framework is discussed as a possible foundation for future development of gravitationand relativistic dynamics.