Would the Aztec and Inca empires have fallen anyway without Cortés and Pizarro, according to Si Sheppard?

Si Sheppard thinks individual battles were contingent: Cortés could have been killed early, and Atahualpa could have kept Pizarro at a distance. But he argues that Eurasian diseases, above all smallpox, which arose from life alongside domesticated animals, would have caused a demographic collapse the empires could not survive. Their subject peoples would then have broken away, and in the long run Europeans would have absorbed the region, perhaps on more balanced terms.

• Sheppard points to Teotihuacan, which rose, overstressed its environment and collapsed, as the cycle he thinks the Aztecs would have repeated.
• Sheppard's main counterfactual is a lasting Norse colony around 1000 that could have passed on iron, horses and disease resistance before the Spanish arrived.

▸In their words

“They could smelt silver and gold to attract the greed of the Spaniards, but they couldn't smelt iron to hold them off.” Si Sheppard · at 48:31 — open in the transcript →

Source: our own transcription of the episode. The full conversation is on Dwarkesh Podcast (2026-10-01). Read the whole episode summary →

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