Symbiogenesis

Margulis's term for the origin of a new kind of organism through lasting symbiosis, as when engulfed bacteria became mitochondria. Agüera y Arcas promotes it in What Is Intelligence? from an episode in cell history to the engine of evolution's arrow: mutation only tunes what a genome already contains, whereas merging opens new combinatorial space, so complexity rises while earlier forms persist inside the composites. His evidence is bff, where byte provenance shows replicators assembling from smaller pieces of code; the hafted spear is the technological analogue. The concept generalizes the Major Evolutionary Transition, AI included, and grounds the "intelligence is symbiotic" thesis and the definition of Life. In the Substack interview he calls the canonical transitions the top of a power law and refuses posthumanist replacement because "everything persists"; the Diffusion statement compresses this into "Symbiogenesis not Skynet," and the Agentworld brief borrows the word for human–agent sociality.