6.1 Two continental firewalls

The Sahara and the Himalayas carve Eurasia into independent information basins. The Himalayas—guarded by the Hindu Kush and faced by the Gobi—separate the Abrahamic sphere from Hindu–Buddhist India and, farther east, the Confucian world. Persia/Iran sits at their crossroads, refining and retransmitting ideas that flow between all three clusters.

Just as renormalisation groups form when internal chatter exceeds external links, these mountains hard-wall information flow, forcing each basin to evolve semi-independently.

6.2 From Rome’s eclipse to the High Middle Ages

The Western Roman collapse (AD 476) coincided with the explosive rise of Islam (7th century), severing Mediterranean sea-lanes that had once knitted Europe, North Africa, and the Levant. The result was a millennium-long reduction in economic and cultural complexity—Europe’s Dark Ages. “Western Europe’s aggregate real GDP per capita fell by roughly 30–40 % between AD 500 and 900, hitting a trough around the 10th century before the long medieval rebound began (Broadberry et al. 2011, Table 1).”

Where Chapter 5 showed Christianity riding Roman roads, here we see what happens when those roads—and the data they carried—snap.

In the High Middle Ages (c. 1000-1300) those broken circuits slowly re-formed. New Italian and Hanseatic trade leagues, Arab–Byzantine intermediaries, and even Crusader corridors re-stitched East–West exchange, setting the stage for a fresh information boom.

This repaired lattice is the runway the printing press will soon roar down.

Medieval Europe was anything but monolithic: kings, nobles, and the Church were rival information clusters. A French monarch still needed baronial coin for wars, and the clergy checked both. The Magna Carta (1215) was primarily elite self-defence, not peasant liberation—a classic illustration of “multi-fractal localism,” where power fractals down to smaller, mutually limiting nodes. “The Magna Carta (1215) was driven less by peasant liberty than by baronial self-defence: the king’s major vassals forced John to concede limits on taxation and arbitrary arrest so they could safeguard their own feudal prerogatives (see Holt 1992, pp. 92–101).”

This mutual throttling echoes the family-tribe-city renormalisation ladder you laid out for political scale.

6.3 The printing press — automated symbol machine

Demand curves slope downward: slash the cost of symbol production and you flood the market with symbols.

Gutenberg’s press (c. 1450) cut manuscript costs by ~90 %. By 1500, Europe had printed ≈ 8 million books, an information explosion impossible under monastic scriptoriums.

Korea’s metal movable-type presses (1230s) and China’s earlier wood-block methods prove that automated symbol tech was not uniquely European—what differed was Europe’s fractured, competitive market for ideas.

Cheaper print shrank the minimum viable “information cluster.” Pamphlets let Luther bypass cathedral pulpits; Swiss and German towns tuned doctrine to local taste; England’s presses stoked Parliamentarian politics.

The press is the first mass-market variable-symbol machine—an ancestor of television’s coloured images and the PC’s two-way icons (Ch. 9 & 11).

6.4 Reformation and Enlightenment — libraries rebooted

The Protestant Reformation germinated in Mainz-Wittenberg, the printing capital of the age. Priests with modest funds could now out-broadcast Rome’s curia. Meanwhile, cheap reprints of Aristotle, Euclid, and Galen—arriving via Arabic translations preserved at Baghdad’s House of Wisdom—fuelled the Enlightenment, which was as much a recovery of lost Greco-Roman knowledge as it was a burst of new theory.

We know from Taleb’s minority rule that the preference of the minority dominates those of the majority if the costs to the majority are not too high. If one in ten at a dinner party doesn’t like sushi, you don’t eat sushi. Scale is determined by the number of nodes in a network needed to sustain the religion. The more people in a network, the greater the set of preferences that the religion needs to appeal to. The greater the set of preferences, the more generic the religion becomes as it has to appeal to the least exclusionary elements of the set. So when religion is created towards a general audience, it has to not offend as many people as possible while capturing as many sets of preferences as possible. The more the content will match the preferences of any one individual, the more time they will spend attending to it. The possibility space of religion increased with the decrease in the cost of communicating information. Smaller religions are, therefore, increasing.

Cheap print widens preference space exactly as cable TV widens niches in Ch. 9, producing both micro-sects and micro-channels.

6.5 Navigation and decentralised ambition

China possessed ocean-going treasure fleets decades before Europe. Admiral Zheng He led seven expeditions (1405-1433); his largest ships dwarfed Columbus’s Santa María (1492). Yet Beijing’s centralised court scuttled the programme after one emperor, while Europe’s political patchwork kept option space wide open with the concept of a company. An Italian navigator could shop his proposal from Lisbon to Seville to London until someone wrote a cheque. Arab lateen-sail technology, spread via the Indian Ocean dhow trade, also underwrote long-distance navigation well before European caravels. But they lacked the capitalist and legalist frameworks of Europe to scale and sustain these trade routes.

Where Rome’s roads synchronised an inland sea, joint-stock charters synchronised planets—stretching the same information-infrastructure argument across oceans.

The next instalment will show how steam, coal, and telegraph cables weld these medieval information shards into the Industrial system whose reflexive loops explode in Chapters 9-11.