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The Ādam Paradox Hypothesis 126
We begin with the genomic evidence of bottlenecks and expansions, then
examine archaeological traces of scaling — beads, harpoons, ornaments,
settlements. We then turn to anthropology and social theory: Dunbar’s number,
gossip, ritual, and institutions. Finally, we weigh the scientific debate and show
how APH resolves it.
By the end, one truth will stand out: numbers alone never made us human.
Symbols did.
The Bottleneck and the Surge
A Narrow Neck of Survival
Modern genomics traces a stark constriction in our past: between ~100,000 and
70,000 years ago, Homo sapiens passed through a severe bottleneck, such that
most people alive today descend from a small survivor pool. This inference
rests on convergent molecular clocks from mtDNA, the Y chromosome, and
whole-genome coalescent analyses, which together indicate an effective
population size plunging to only a few thousand breeding individuals (Henn,
Cavalli-Sforza, & Feldman, 2012).
Why did this happen?
One candidate event is the Toba super-eruption, a volcanic explosion ~74,000
years ago on the island of Sumatra. Toba was one of the largest eruptions of
the Quaternary period, ejecting roughly 2,800 cubic kilometers of ash and
aerosols into the atmosphere. For comparison, the 1980 eruption of Mount St.
Helens expelled just 1 km³
— making Toba nearly 3,000 times larger in scale.
Ash layers traceable to Toba are found from the Indian Ocean to the Arabian
Sea, and climatic models suggest the eruption could have plunged the planet
into a volcanic winter, cooling temperatures by several degrees for decades.
In his influential 1998 paper, Stanley Ambrose proposed a direct link between
Toba and the human bottleneck:
“The eruption reduced human populations to a few thousand individuals, creating a genetic
bottleneck that shaped all later humanity.
” (Ambrose, 1998, p. 623)