# Hixon Symposium > **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:** History of Science / Neuroscience **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition The 1948 Hixon Symposium on Cerebral Mechanisms in Behavior at Caltech brought mathematicians, neuroscientists and psychologists together around the organization of brains and behavior. ## Nexus Context John von Neumann’s September 1948 contribution framed reliable self-reproduction and complexity in automata before molecular biology had identified DNA’s structure. ## Evidence Boundary The symposium establishes chronology and intellectual context; it does not show that Watson, Crick or molecular biologists derived their work from von Neumann. ## Relationships [[wiki/Caltech|Caltech]], [[wiki/John von Neumann|John von Neumann]], [[wiki/Cellular Automata|Cellular Automata]], [[wiki/Molecular Biology|Molecular Biology]] ## Sources / Provenance - Jeffress, ed., _Cerebral Mechanisms in Behavior_ (1951); PNAS historical analysis of Turing and von Neumann.