# Critical Infrastructure
**Domain:** Infrastructure / Security / Public Policy
**Doc Type:** Concept Node
**Maturity:** Developed
## Definition
**Critical infrastructure** consists of systems whose incapacity or destruction can produce disproportionate harm to public safety, continuity, economic life or institutional function.
Criticality is relational rather than a permanent property of an object. A modest component can become critical when many systems depend on it, substitutes are unavailable or recovery time exceeds the tolerance of the functions it supports.
## Governing Variable
The governing variable is continuity of essential function under disturbance.
## Material and Institutional Manifestation
Power, water, telecommunications, transport, finance, health, food, government services and computation can become critical through dense dependency. Ownership may be public or private; operational responsibility and public consequence often cross that boundary.
## Computational Analogue
Dependency graphs, failure domains and service-level objectives make some critical relations machine-readable. The model remains incomplete if it ignores labor, repair supply chains, legal authority or informal workarounds.
## Constitutional Question and Failure Modes
Security can justify secrecy, but excessive opacity can prevent public accountability and shared learning. Other failure modes include common-mode dependencies, deferred maintenance, capture by operators and protection plans that preserve assets while abandoning dependent communities.
## Related Ontology
[[wiki/Infrastructure as Executable Social Order|Infrastructure as Executable Social Order]] · [[wiki/Utility Infrastructure|Utility Infrastructure]] · [[wiki/Infrastructure as Power|Infrastructure as Power]] · [[wiki/Cyber-Physical System|Cyber-Physical System]]