Redundancy in necessary components makes systems more stable.

Evidence

Cioffi-Revilla (1998) stresses that substitutability is related to redundancy in systems (e.g., Bendor 1985; Landau 1969). Systems are more stable if necessary components have backups and alternative sources. An example is US nuclear deterrence via the triad of air-, land-, and submarine-based weapons. If one or two legs of the system were to be taken out by attack, there is enough redundancy in the system to give the United States a second strike capability (Cioffi-Revilla 1998). — Gary Goertz, Social Science Concepts and Measurement, 1539

Categorization

• CANDY: The nuclear triad as a tidy illustration of functional redundancy that survives losing two of three legs, good elevator material.
• XREF: Connects to systems theory and reliability engineering’s standby-redundancy literature.