# Christopher Langton > **Machine-Evolution Nexus:** [[articles/Digital Darwinism and the Invisible World of Machine Evolution|Digital Darwinism and the Invisible World of Machine Evolution]] places this node within the history and governance of substrate-independent evolution. **Domain:** Artificial Life / Computation **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition Christopher Langton is a computer scientist who helped establish artificial life as a field and developed a small self-reproducing cellular-automaton loop. ## Nexus Context Langton’s loop showed that nontrivial self-reproduction does not require universal construction. Its descendants provided the architecture Sayama modified into Evoloops. ## Evidence Boundary A self-replicating loop is not automatically Darwinian; viable inherited variation and population-level selection mark the later threshold. ## Relationships [[wiki/Self-Replicating Loop|Self-Replicating Loop]], [[wiki/Evoloop|Evoloop]], [[wiki/Artificial Life|Artificial Life]], [[wiki/Hiroki Sayama|Hiroki Sayama]] ## Sources / Provenance - Langton, “Self-Reproduction in Cellular Automata,” _Physica D_ 10 (1984).