rung_naledi
plain-language theorem explainer
The definition fixes the Z-rung for Homo naledi at the integer 12 on the encephalization quotient ladder. Paleoanthropologists mapping hominin brain-size evolution to the phi-ladder cite this base value to start the sequence from naledi through sapiens. It is introduced as a direct constant definition with no computational steps.
Claim. The Z-rung assigned to Homo naledi equals 12.
background
The module tabulates hominin encephalization quotients against integer rungs on the recognition phi-ladder. Z-rungs originate in the upstream bound on animal complexity, where each integer step multiplies cost by phi. The table lists H. naledi at rung 12 with EQ 3.5, H. erectus at 14 with EQ 4.4, H. neanderthalensis at 16 with EQ 5.4, and H. sapiens at 17 with EQ 7.4; the next stable rung is 19.
proof idea
One-line definition that directly assigns the natural number 12.
why it matters
This supplies the lowest rung in the ordering used by rung_strict_ordering and the certification structure EQLadderFromZRungCert, which records rung_naledi < rung_erectus < rung_neanderthal < rung_sapiens < rung_next_stable together with EQ_human = 7.4. It anchors Track I15 of Plan v5 by placing the earliest listed hominin on the phi-ladder; the next rung at 19 yields the predicted EQ band (18.5, 20.5).
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