The political cosmology of legitimacy granted and withdrawn by Heaven.
The Mandate of Heaven holds that Heaven grants a ruler the right to govern only so long as he rules justly; misrule, disorder, and disaster are signs the mandate is being withdrawn, and a successful rebellion proves it has passed to another. Legitimacy is conditional and revocable, never owned.
Tianming unlocks a moral feedback loop inside politics: authority is tied to performance and virtue rather than blood alone, and failure is, in principle, falsifiable. It built a right of rebellion into the heart of imperial ideology — a cosmology that could both crown a dynasty and, by the same logic, end one.