# Machine Language > **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:** Computing / Execution **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition Machine language is an instruction representation executed directly or virtually by a processor architecture. ## Nexus Context Tierra’s genomes are machine-language instruction sequences whose execution performs replication and whose copy errors can become inherited behavioral variation. ## Evidence Boundary Instruction meaning depends on an interpreter. The same bits outside the compatible virtual machine are inert archive, a direct example of hot interpreter versus cold description. ## Relationships [[wiki/Tierra|Tierra]], [[wiki/Genome|Genome]], [[wiki/Hot Interpreter and Cold Archive|Hot Interpreter and Cold Archive]], [[wiki/Operational Substrate|Operational Substrate]] ## Sources / Provenance - Computer-architecture texts; Ray (1991).