This preprint presents Cai's Law, a novel alternative gravity theory, along with three testable, falsifiable predictions related to black hole observations, gravitational waves, and cosmic large-scale structure. All predictions are verifiable using existing astronomical detection equipment, and this paper serves as the core theoretical foundation of the Cai's Law framework. A supporting philosophical study on the nature of time, a key premise of the theory, is available at: https://zenodo.org/doi/10.5281/zenodo.20594109.