# Self-Replicating Program > **Machine-Evolution Nexus:** [[articles/Digital Darwinism and the Invisible World of Machine Evolution|Digital Darwinism and the Invisible World of Machine Evolution]] places this concept within the history and governance of substrate-independent evolution. **Domain:** Software / Digital Evolution **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition A self-replicating program is executable code that causes copies of its operative instructions to be created. ## Machine-Evolution Context Tierra and Avida use controlled self-replicating programs as digital organisms; worms use similar capacity across real networks. Heritable variation and selection determine whether replication becomes evolution. ## Continuity and Evidence Boundary Self-replication creates operational and security risk without implying agency. Containment should govern replication channels, permissions and resources rather than anthropomorphizing code. ## Relationships [[wiki/Morris Worm|Morris Worm]], [[wiki/Digital Organism|Digital Organism]], [[wiki/Self-Replication|Self-Replication]], [[wiki/AI Safety|AI Safety]] ## Sources / Provenance - Thomas Ray (1991); FBI history of the Morris Worm.