The short answer to the titular question, “Why the West rules?”, is “geography” (557), according to Morris. He elaborates that humans are, like all animals, “inquisitive but also greedy, lazy, and fearful” (557). Morris argues this is universal to both East and West, and 19th- and 20th-century theories that Westerners were innately superior due to biological factors are incorrect.

Societies are motivated by people’s desire to make “their lives easier or richer” or they are “struggling to hold on to what they already have as circumstances change, and, in the process, generally nudging social development upward” (559). In Morris’s view of history, this is the key motivation for social movements and technological changes, from settled agricultural communities to the Industrial Revolution.

The problem is what Morris describes as a “paradox” where social development gives rise to developments that eventually undermine it, which Morris describes as “hard ceilings” (560). The pattern only ended once industrialization and fossil fuels ended the limits on how much primarily agricultural societies can develop.

After summarizing his overall thesis, Morris addresses the “most obvious objections” (561). One of these is the matter of human agency. Individual choices adding up to collective ideas, like the decisions of over a billion women to have fewer or no children in recent years, can change history. However, Morris adds that “[t]here are strong pressures on all of us to make choices that conform to reality” (566).

There are individuals whose lives and decisions have tremendous consequences, like the prophet Muhammad. Still, Morris posits that Muhammad’s historical impact was also made possible by previous movements toward monotheistic religion in Arabia, the Mediterranean region splitting into disparate states, and the decline of the Persian and Byzantine empires.

This is also true for history’s great thinkers. Morris argues that they simply draw from similar ideas and methods, something shown by how an “extraordinary number of modern inventions” are “made more than once” (568). Morris argues that innate cultures do not shape history anymore than innate biology. Instead, “the histories of Eastern and Western thought have been broadly similar across the last five thousand years” (569).

To arguments that Islam itself has led to the decline of the Islamic world, Morris counters that Islamic societies produced tremendous scientific advancements in the early Middle Ages and that Islamic societies vary widely, with Turkey as an example of a Muslim-majority country that embraced modernity. Instead, Morris suggests that “since 1700 many Muslims have turned inward in response to military and political defeat, just as many Chinese Confucians did in the thirteenth and fourteenth centuries” (571).

Next, Morris summarizes his reasons for the rise of the West by going backward in time. In the 18th century, Napoleon conquering Britain might have slowed the Industrial Revolution or caused it to unfold in northern France instead, but he thinks nothing after 1800 could stop it.

Around 1500, Morris thinks that, if Charles V had managed to consolidate his control over Europe, it might have stifled colonial trade and led to the successful persecution of the sort of thinkers who kicked off the Scientific Revolution and the Enlightenment. Similarly, if the Ottomans had conquered Europe, the center of trade might have stayed in the Mediterranean, or if the Ottomans and Russia had fought each other more than in our history, the steppes might not have been conquered. In such a scenario, the Mongols might have been driven into Europe by the rise of the Qing in China, leading to a new European “dark age” (574) while the Chinese industrialized.

1350 offers even more possible alternate history situations, like if the Mongolian conqueror Tamerlane had attacked Italy or succeeded in conquering China, or if China had remained a clutch of warring states competing with each other. The further back one goes in history, the more “wild cards” (575) there are.

For Morris, the most likely turning point where the East could have eventually industrialized was 1100. Had the Song dynasty survived or if Genghis Khan had never lived, then Chinese history might have gone on a trajectory that would have led to the East overtaking the West. However, Morris believes that geography always made it more likely the West would take that jump. The only thing that would have prevented anything like the Industrial Revolution and the rise of the West would have been catastrophic climate change or an asteroid hitting the planet.