# Self-Replicating System > **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:** Computation / Biology / Continuity **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition A self-replicating system is an organized process that produces another operational instance sufficiently similar to continue the copying lineage. ## Machine-Evolution Context The definition includes a system’s dependence on external materials and machinery. No replicator is literally self-sufficient; the question is which causal work belongs to the replicator and which to its environment. ## Continuity and Evidence Boundary Replication fidelity, inherited variation and competition determine whether the system can evolve. Identity and moral status remain separate questions. ## Relationships [[wiki/Self-Replication|Self-Replication]], [[wiki/Replicator|Replicator]], [[wiki/Universal Constructor|Universal Constructor]], [[wiki/Receiving Substrate|Receiving Substrate]] - **Historical application:** [[wiki/Advanced Automation for Space Missions|NASA CP-2255]] proposed a self-replicating lunar factory; [[collections/MARS|MARS]] and [[articles/The Last Migration Will Not Be Human|The Last Migration Will Not Be Human]] develop the off-world infrastructure route. The NASA study did not report a deployed factory. ## Simple Reminders, Quotations, and Thoughts > “NASA is in a unique position to benefit from massive automation — particularly self-replicating systems.” > **— NASA/ASEE Summer Study**, *1980 study; published 1982 in Advanced Automation for Space Missions, §5.6.1* [[reminders/Space Survival/NASA Saw Self Replicating Systems as a Space Advantage by NASA ASEE Summer Study|NASA Saw Self Replicating Systems as a Space Advantage by NASA ASEE Summer Study]] From [[wiki/Darwin Among the Machines|Darwin Among the Machines]]: This deliberately strange image introduces the reproductive-system analogy developed in the following passage. > "There is nothing which our infatuated race would desire more than to see a fertile union between two steam engines." > **— Samuel Butler**, *1863, “Darwin Among the Machines,” The Press, Christchurch* [[reminders/Evolution/Butler Imagined a Fertile Union Between Steam Engines by Samuel Butler|Butler Imagined a Fertile Union Between Steam Engines by Samuel Butler]] From [[wiki/Darwin Among the Machines|Darwin Among the Machines]]: Butler points to machines used to manufacture other machines, not to autonomous reproduction by a completed machine lineage. > "It is true that machinery is even at this present time employed in begetting machinery, in becoming the parent of machines often after its own kind." > **— Samuel Butler**, *1863, “Darwin Among the Machines,” The Press, Christchurch* [[reminders/Evolution/Machinery Was Already Begetting Machinery by Samuel Butler|Machinery Was Already Begetting Machinery by Samuel Butler]] From [[wiki/Erewhon|Erewhon]]: Butler argues by functional definition rather than by biological resemblance. > "Surely if a machine is able to reproduce another machine systematically, we may say that it has a reproductive system. What is a reproductive system, if it be not a system for reproduction?" > **— Samuel Butler's Erewhonian professor**, *1872, Erewhon, Chapter XXIV* [[reminders/Evolution/A Reproducing Machine Has a Reproductive System by Samuel Butler|A Reproducing Machine Has a Reproductive System by Samuel Butler]] From [[wiki/Erewhon|Erewhon]]: The analogy shifts the unit of analysis from a single artifact to an organized society of components. > "We are misled by considering any complicated machine as a single thing; in truth it is a city or society, each member of which was bred truly after its kind." > **— Samuel Butler's Erewhonian professor**, *1872, Erewhon, Chapter XXIV* [[reminders/Cybernetics/A Complex Machine Is a City of Parts by Samuel Butler|A Complex Machine Is a City of Parts by Samuel Butler]] ## Sources / Provenance - von Neumann (1966); Sayama and Nehaniv (2025).