Debunking Guns, Germs, and Steel: Genes Not Geography Shape Civilizations
Debunking "Guns, Germs, and Steel"
Jared Diamond’s Guns, Germs, and Steel (1997) argues that environmental factors – geography, available resources, domesticable plants and animals, and germs – explain why some societies advanced faster than others.
Diamond famously dismisses any role of innate population differences, stating:
“History followed different courses for different peoples because of differences among people's environments, NOT because of biological differences among peoples themselves.”
This report challenges Diamond’s core claims using evidence from aggregate genetics and real-world outcomes. By examining cross-national data on cognitive ability, personality traits, social trust, and innovation, we find that inherited group traits have a powerful influence on societal development – often contradicting purely environmental explanations.
We use first-principles reasoning and empirical evidence to show that environment alone cannot account for global inequality, and that ignoring human genetic differences leads to misleading historical narratives.
I. Environmental Determinism vs. Human Capital
Diamond’s Claim: Geography and the environment determined the fate of societies. Eurasia’s east–west continental axis and richer suite of domesticable species gave its peoples a head start, whereas other regions lagged due to environmental handicaps. In Diamond’s view, this environmental determinism is the ultimate cause of Eurasian dominance, not any differences in the people themselves.
Counterargument: While geography and resources influenced early development, they are insufficient to explain the persistent gaps in achievement across regions.
Many areas with favorable geography or abundant resources failed to develop advanced civilizations or modern prosperity, whereas some resource-poor regions thrived.
For example: the Democratic Republic of Congo (DRC) is endowed with vast mineral wealth (untapped deposits worth trillions of dollars), yet it remains one of the world’s poorest countries (Economy of the DR of the Congo).
In contrast, a resource-scarce nation like Japan (lacking significant oil or minerals) became an economic and technological powerhouse.
1.) Geography alone cannot account for such outcomes. Instead, human capital and population traits were decisive:
Regions like central Africa had rich natural endowments but did not industrialize, suffering from instability and poor institutions despite their potential. As one analysis notes, “despite being home to vast potential in natural resources and mineral wealth,” the DRC’s GDP remains minuscule and it is “one of the poorest countries in the world”. Clearly, natural riches were not enough to ensure development.
By contrast, places where European settlers migrated en masse (North America, Australia, etc.) often flourished economically. Crucially, settlers brought their skills, institutions, and genetic predispositions (such as higher average IQ and future orientation) to these new lands. Where settler populations could not take root – for example, much of tropical Africa where disease deterred settlement – colonial powers left extractive institutions that persisted in dysfunction (Colonial Origins of Comparative Development). This suggests the presence (or absence) of certain peoples and institutions mattered more than the soil or latitude alone.
2.) Empirical studies reinforce that population quality drives development more strongly than geography
Researchers Richard Lynn and Tuomas Vanhanen found extremely high correlations (around 0.70) between national average intelligence and GDP per capita (Lynn & Vanhanen, 2006) — findings that were further supported by additional research. (Gaygisiz & Lajunen, 2022).
In other words, countries with higher cognitive skill populations tend to be much richer, regardless of their geographic location.
High national IQ has been linked not only with greater wealth but with higher rates of innovation (e.g. scientific publications and patents) (Templer & Rushton, 2011) and more effective institutions (we will elaborate on these points later).
If geographic luck were solely determinative, we would not expect such a strong connection between intangible human traits and economic output.
From a first-principles perspective, environment is a backdrop, not destiny.
Humans adapt to challenges: a harsh environment can spur innovation (e.g. cold climates necessitating better housing, clothing, storage), while a bountiful environment can be squandered without the cultural or genetic traits to capitalize on it.
The fact that small, geographically modest nations (like England or the Netherlands) spearheaded the Industrial Revolution, while geographically vast and earlier-civilized regions (like the Fertile Crescent or India) fell behind by the modern era, underscores that human factors overtook geographic initial conditions. It is true that geography may have (in some cases) set the stage, but human capital and aggregate genetic traits decided which societies stole the show.
II. Guns, Germs, and… Genes? The Role of Diseases
Diamond’s Claim: Infectious diseases (“germs”) shaped historical power dynamics. Eurasians acquired lethal germs from domesticated animals and dense settlements; when they encountered other continents (the Americas, Oceania, sub-Saharan Africa), their diseases decimated local populations, easing conquest. Thus, epidemiological luck – not any inherent superiority – allowed Europeans to colonize large parts of the world.
Counterargument: Disease environments impacted conquests, but they do not provide a lasting explanation for technological and organizational superiority
Germs were essentially an exogenous shock to native peoples, one that equalized over time (populations either developed immunity or died out).
After the initial epidemics, the long-term dominance of certain civilizations relied on innovation, governance, and economic productivity – areas in which human traits play a central role.
Several points undermine the idea that germs alone determined the fates of societies.
1.) Throughout history, disease outbreaks afflicted all populations, yet not all responded equally.
For instance, the Black Death in medieval Europe killed a large share of the population, but Europe rebounded with improved productivity and eventually used the crisis to innovate (e.g. labor-saving technologies).
This hints that European society’s resilience and ingenuity – possibly bolstered by traits like higher future orientation and problem-solving ability – allowed it to learn from catastrophe rather than collapse.
2.) If germs were the decisive factor in conquest, one would expect that once the “gunpowder empires” established themselves (often aided by disease die-offs among the conquered), the conquered regions would eventually catch up once they acquired the same animals, crops, and immunity.
Yet we see persistent gaps: for example, Latin American countries gained Eurasian livestock and crops 500 years ago, but their development still lags behind Western Europe and North America.
Something beyond the initial germ shock has kept these gaps in place – namely differences in institutions and human capital that trace partly to the colonizing populations and the indigenous populations’ historical background.
3. European success over the long run also involved overcoming disease in reverse – for example, in the 19th century, Europeans suffered high mortality in Africa (“white man’s grave”) due to tropical diseases.
But advances in science (quinine for malaria, improved sanitation) allowed them to survive and govern in environments previously lethal to them.
This scientific progress was driven by European researchers and physicians – again a testament to knowledge and innovation as critical factors.
In the 20th century, it was mostly Western-led efforts that eradicated or controlled diseases worldwide (e.g. smallpox vaccination).
If germs determined fate, one might ask: Why didn’t the historically disease-plagued regions pioneer the cures?
The answer circles back to disparities in education, cognitive skills, and social capacity for large-scale problem-solving.
Overall, germs affected when and how conquests happened, but not why some peoples were in a position to conquer in the first place. Europe’s advantages in metallurgy, shipbuilding, and military organization cannot be reduced to microbes – they required human creativity and cooperation built up over centuries. Those human factors are better explained by genetic evolution and culture (downstream of genetics) (which produced differences in skills, foresight, and social cohesion) than by the geographic happenstance of pathogen exposure alone.
III. Agriculture & Food Surpluses – Necessary but Not Sufficient
Diamond’s Claim: The emergence of agriculture – and the resultant food surpluses – was the primary catalyst for complex societies. Regions that domesticated plants and animals early (the Fertile Crescent, China, etc.) gained large, sedentary populations and specialization of labor, leading to cities, technology, and state institutions. In contrast, regions that remained hunter-gatherers or had late/agriculturally poor starts (like New Guinea or Aboriginal Australia) did not develop complexity simply due to this agricultural timing gap.
Counterargument: Agriculture was indeed a prerequisite for large civilizations, but it does not fully explain the variance in societal complexity and progress.
Many parts of the world adopted agriculture, yet their outcomes diverged enormously.
Clearly, factors beyond the mere presence of farming – such as population traits and cultural evolution – influenced which societies made the leap to advanced technology and industrialization.
The most obvious question for Diamond is: “Why did agriculture emerge in certain societies before others? And why were some more skilled than others?” (“Culture”? What causes culture? Magic. Oh yeah.)
Consider the following counterpoints.
1.) Multiple Origins, Divergent Paths
Agriculture independently arose in at least several regions (the Fertile Crescent, East Asia, Mesoamerica, Andes, possibly sub-Saharan Africa with yam/sorghum domestication). However, these cradles of agriculture had very different trajectories.
The Middle East (Fertile Crescent) was an early leader but later stagnated; East Asia and Europe surged ahead in later millennia; Mesoamerican and Andean civilizations peaked and then fell behind technologically after contact.
If surplus food automatically led to sustained advancement, one would expect the first farming societies to maintain their lead indefinitely.
Instead, we see innovation clusters shift over time, suggesting that people’s traits and decisions (shaped by evolutionary and cultural pressures) directed how surplus was used.
2.) The Utilization of Surplus
Food surplus enables specialization, but it does not guarantee how that specialization is directed.
Societies with higher average intelligence, creativity, or openness to change may channel surplus labor into experimentation, invention, and complex institutions.
Societies lacking those traits might instead channel surplus into simply increasing consumption or maintaining a larger but still technologically stagnant population.
For example, throughout the early modern period, China had massive agricultural surpluses and was economically richer than Europe in many respects, yet Europe underwent the Industrial Revolution first.
Some historians argue that cultural factors (and by extension, underlying psychological traits) made Europeans relatively more inclined toward scientific experimentation and capital investment, whereas late-imperial Chinese society prioritized stability and bureaucratic control.
Thus, same surplus, different outcomes, due to human differences. (“Cultural factors” are just groups of behaviors determined by aggregate population genetics in response to environments.)
3.) Agriculture as an Effect, not just Cause
It’s plausible that populations with certain predispositions were more likely to adopt intensive agriculture in the first place.
Groups that were more future-oriented and high in impulse control might be better at the delayed gratification farming requires (plant in spring, harvest in fall, store for winter) compared to nomadic lifestyles.
Those groups would settle, grow, and outcompete others – a possible case of gene-culture coevolution.
Over thousands of years, farming itself applied selection pressures: it rewarded planning, cooperation in larger communities, and resistance to diseases that thrive in dense settlements.
Thus, populations with a 10,000-year history of dense agriculture (e.g. Eurasians, East Asians) underwent more generations of selection for those traits than populations that remained pastoral or hunter-gatherer until recently.
In essence, the advantages of agriculture eventually became encoded in the populations practicing it, in addition to the immediate caloric boost.
Diamond’s narrative treats agriculture as a lucky kickstarter, but the fuller picture is that agriculture and population traits evolved together, reinforcing advantages for some groups beyond what geography alone bestowed.
Overall, agriculture was an enabling factor, but the primary catalysts of sustained societal complexity were the people managing that agriculture. Food surplus opened the door; human innovation, social structure, and foresight determined who walked through it. The failure of some early civilizations to industrialize, and the success of some later starters, illustrates that human capital became the limiting factor once basic environmental needs were met.
IV. Aggregate Genetic Differences as Causes of Development
If environmental determinism falls short, what fills the gap?
The alternative thesis is that aggregate differences in genetically-influenced traits across populations significantly affect societal outcomes.
These traits – including cognitive ability, personality factors like conscientiousness and risk-taking, and social behaviors like trust and cooperation – vary in distribution among groups.
Modern behavioral genetics and psychometric research indicate substantial heritability for these traits within populations, and measurable differences between populations.
A.) Cognitive Ability & Innovation
One of the most studied cross-national differences is in general cognitive ability (IQ). A century of testing has found that populations do not all have the same average IQ. (Henss, 2024) (Lynn & Meisenberg, 2010)
(From an evolutionary perspective, this is neither good nor bad… it just “is” how various populations were shaped evolutionarily over time.)
Broadly, East Asian populations (e.g. in China, Japan, Korea) score the highest, European and European-descended populations score somewhat lower but still high, and many populations in sub-Saharan Africa score lower on average.
For example, East Asian nations typically average IQs around 105–110, European populations around 100, and sub-Saharan African populations around 70–85 on tests normed to a Western mean of 100.
These differences are robust across studies (though exact values can vary with testing conditions). Crucially, they correlate strongly with real-world indicators of technological and economic performance.
Economic Output: National IQ has a correlation ~0.7 with GDP per capita. In plainer terms, high-IQ countries are far more likely to be wealthy and economically productive than low-IQ countries. This relationship holds even when controlling for measures of education and institutions, suggesting average cognitive ability has an independent effect on a nation’s prosperity. A high collective IQ likely translates to a more skilled workforce, better decision-making, and more innovation.
Innovation & Scientific Achievements: Higher average IQ populations produce disproportionate shares of scientific research, patents, and technological inventions. One analysis found that national IQ correlates with the number of scientific papers and patents a country produces. It makes sense that a more cognitively able population can push the frontiers of knowledge faster. Additionally, virtually all winners of Nobel Prizes in science have come from high-IQ populations (Europe, North America, Northeast Asia), reflecting the underlying talent pool necessary for such breakthroughs.
Historical Insight: The distribution of intelligence appears to map closely onto the cultural and economic history Diamond tries to explain. As J.P. Rushton pointed out in a critique of Diamond, “well documented racial differences in brain size and IQ map very closely to the same cultural histories Diamond is at such pains to try to explain” (Rushton, 1999). In other words, the regions that historically lagged in “guns, germs, and steel” also tend to have lower average cognitive ability, which Diamond attributes solely to environment. But evolutionary reasoning suggests environment and biology are linked – different environments over millennia produced different genotypic aptitudes.
It’s important to note that these IQ differences are aggregate and statistical; there is enormous overlap in individuals, and any population has geniuses and dullards.
However, when we talk about societal outcomes, it is the average and the proportion of high-ability individuals that often shape a country’s trajectory (sometimes called the “smart fraction” theory).
A nation with more engineers, inventors, and effective managers will outpace one with fewer, even if both have their share of talent. Aggregate genetics influences the size of that talent pool.
Additionally, recent genetic research reinforces that these cognitive differences are not just an artifact of environment or test bias. Genome-wide association studies (GWAS) have identified many genetic variants associated with educational attainment and cognitive ability. (Piffer, 2019)
By combining these into polygenic scores, researchers can predict a significant portion of IQ differences. Strikingly, when such polygenic scores are compared across ancestral populations, they mirror the IQ hierarchy measured by tests.
One study found that a polygenic index for educational attainment was highly predictive of average national IQ (r ≈ 0.90 across populations).
In fact, the genetic score explained roughly twice as much of the variance in national IQ as socioeconomic factors did. Another analysis showed East Asian and European populations have higher frequencies of alleles associated with greater cognitive ability or educational success than African populations.
These findings support a genetic component to global intelligence differences. They indicate that evolution in different environments (for example, under the pressures of agrarian states or harsh climates) likely selected for different levels of cognitive abilities.
Intelligence, in turn, feeds directly into a society’s capacity for innovation and complex problem-solving.
B.) Conscientiousness, Impulse Control, Time Preference
Cognitive ability is only one facet of human capital. Equally important are personality traits and time horizons that affect behavior on a mass scale.
Traits like conscientiousness (industriousness, reliability) and low time preference (impulse control, ability to delay gratification) vary between cultures and have some heritable basis. (Hubler, 2018)
These traits influence work ethic, savings and investment behavior, crime and corruption levels, and overall social stability.
Consider delayed gratification. On a larger scale, cultures differ in their willingness to sacrifice present comfort for future gain. East Asian cultures, for example, have been noted for high savings rates and emphasis on education (a long-term investment), reflecting a long-term orientation. In contrast, societies that exhibit more short-termism may struggle to accumulate capital or maintain functional institutions (since corruption or rent-seeking – essentially, grabbing benefits now at the expense of the future – will be more common).
These cultural differences often overlap with population genetic differences shaped by history. A “harsh winter” evolutionary scenario posits that populations in cold climates had to plan ahead (store food, build shelter) or perish, thereby selecting for individuals with greater impulse control and conscientiousness.
Indeed, researchers Templer and Arikawa found that national IQ was negatively correlated with average winter temperature (r ≈ –0.76), supporting the idea that cold climates selected for higher intelligence and by extension forward-planning abilities.
While IQ was the measured variable, the scenario implies selection for a suite of traits – patience, diligence, cooperative planning – necessary for survival in seasonal environments. Populations in year-round tropical climates, by contrast, faced fewer seasonal survival pressures (food was often continually available, though they battled diseases).
Over many millennia, such differing pressures likely led to measurable personality differences. It’s telling that today, countries with hotter climates not only have lower average IQs but also score lower on indices of future orientation (for example, lower savings rates or higher rates of behaviors that prioritize short-term gains).
The alignment of climate, genetic, and behavioral data is suggestive. Thinking that “culture” is responsible fails to understand that “culture” is a byproduct of aggregate population genetics (genetics of a population → cognition/behavior patterns in response to environment → “culture”).
Empirically, we see the impact of these traits in economic behavior and governance. High-conscientiousness, low-impulsivity societies tend to have lower corruption and more stable institutions, because officials and citizens are willing to follow rules and forego immediate temptation for long-term benefits.
There is evidence that national IQ (a proxy that combines cognitive ability and perhaps some trait influences) correlates with lower corruption partly because smarter populations have longer time horizons and understand the value of rule of law.
In one cross-country analysis, a 10-point IQ advantage was associated with significantly less corruption, mediated by greater patience and future-oriented outlooks of the populace. (Read: Genetics of Corruption)
As a concrete example, consider savings and investment: East Asian countries (China, Korea, Japan, etc.) for decades have had savings rates often above 30% of GDP, fueling higher investment and growth.
In contrast, many Latin American or African countries have savings rates in the teens or single digits, with capital often fleeing those countries.
While numerous factors are at play, one contributing element is differing collective time preferences – how much people value the future.
Higher self-control (whether culturally instilled or genetically predisposed) allows East Asian societies to defer gratification and build capital for the future, whereas a culture of immediacy hampers long-term growth elsewhere.
These patterns correlate with both cultural values (e.g. Confucian ethos) and possibly genetic temperament differences (as suggested by the “Cold Winters” evolutionary theory and genetic clustering of such traits).
In short, societal industriousness and prudence are not evenly distributed around the globe. Populations that, for historical or genetic reasons, have greater average impulse control and conscientiousness reap the benefits in more efficient economies and governments. These traits help explain why agriculture’s fruits were used so differently across populations – some turned surpluses into lasting civilizations, others into short-lived booms and busts.
C.) Social Trust, Cooperation, Social Capital
Complex societies depend on cooperation beyond kinship. This requires a level of social trust – believing that strangers or distant others will follow shared norms and reciprocate fairness.
Diamond’s account gives germs and geography as the glue of large societies, but it downplays the role of psychological traits enabling cooperation.
Research in social science has repeatedly shown that high levels of generalized trust and prosocial attitudes greatly facilitate economic development and good governance.
Here too, we find large cross-cultural differences that align with population histories.
Modern survey data (e.g. the World Values Survey) reveal a striking trust gap across nations. In the highest-trust societies – typically homogeneous, developed nations – a majority of people agree that “most people can be trusted.”
In Scandinavia, over 60% respond that way. In contrast, many low-trust societies – often in the developing world – see less than 10% of people expressing trust in the general population. (Global Preferences Survey)
For example, Sweden boasts around two-thirds of citizens who trust others, whereas Brazil reports well under 10%. This is a monumental difference in social outlook.
High-trust populations can more easily create effective institutions, enforce contracts, and engage in large-scale collective projects, because people feel confident cooperating with those beyond their immediate family.
Low-trust populations tend to fragment into clannish or zero-sum behaviors: nepotism, corruption (trusting only your in-group to look out for you), and difficulty in maintaining public goods.
Higher trust societies (toward the top of the chart) overwhelmingly enjoy higher economic output per person. For instance, Scandinavian countries (blue dots at top-right, e.g. Denmark, Norway) combine high trust (~70%) with high GDP.
In contrast, countries like Nigeria and Brazil (green/pink dots at bottom-left) have very low trust (under 20% saying most people can be trusted) and much lower GDP. The strong positive relationship indicates that trust is a key form of social capital underpinning prosperity. (Link between trust & economic prosperity, 2021)
What are the roots of these trust differences? Likely genetic. Populations that spent millennia in large, relatively stable societies may have undergone selection for more prosocial temperament – individuals who were better at adhering to social norms and cooperating could out-reproduce antisocial individuals in an organized state.
Conversely, populations in very fragmented or turbulent environments might evolve more suspicion and clannishness as a survival strategy.
One intriguing line of research links the long history of outbreeding versus inbreeding to societal trust: medieval European populations, influenced by Church bans on cousin marriage, developed more individualistic and trusting societies (by breaking tight kin bonds), whereas parts of the world that retained cousin marriage and tribal structures fostered more inward-focused loyalties.
These cultural practices, persistent over generations, likely also affected the gene pools – selecting for people inclined toward broader versus narrower social circles of trust.
The net effect today is that some populations show markedly higher innate social cohesion than others. Northern European societies, Japan, and a few others are noted for citizens following rules even when not watched – an orientation some call “generalized morality.”
By contrast, in societies where trust is low, people may default to cheating the system if not strictly controlled – because they assume others will do the same. The outcome is weaker institutions and difficulty in achieving large-scale cooperation.
For instance, corruption is almost endemic in low-trust countries, feeding a vicious cycle of distrust. Empirical studies confirm that countries with high-trust cultures have significantly lower corruption and more effective governments than low-trust cultures.
In one meta-analysis, a 10% increase in trust was associated with a 0.5% higher annual GDP growth – a huge effect over decades.
Diamond credited germs for Europeans’ advantages, but an alternate view is that Europe (especially Northwest Europe) succeeded in part because it evolved into a high-trust, corporate society. This allowed the development of inclusive institutions, impersonal markets, and nation-states capable of mobilizing resources – advantages that low-trust, fragmented societies could not match easily.
Aggregate genetics likely underpin this: traits of empathy, fairness, and social reciprocity have genetic components (e.g. polymorphisms affecting oxytocin receptors or other neurochemicals influence social bonding). As groups diverged, those traits’ frequencies likely shifted, reinforcing cultural differences. Thus, germs did not make Europeans obey contracts and invest in joint-stock companies – their social genes and norms did.
D.) Innovation, Exploration, Risk-Taking
A final genetic trait cluster worth examining is openness to new ideas, willingness to take risks, and industriousness.
History’s great leaps – geographic exploration, scientific revolution, industrialization – required not just brains and trust, but also a spirit of innovation and enterprise. Populations differ in these inclinations too.
Why did the Europeans embark on the Age of Exploration and not the Chinese or Indians, who were equally advanced until the 15th century?
Chinese explorers like Zheng He did conduct voyages, but China then turned inward. Some historians cite cultural-political causes (the emperor’s edict, etc.), but one can also ask if there were personality differences on average.
Europeans of that era, especially Western Europeans, showed a pronounced hunger for adventure, profit, and even failure in pursuit of success – countless voyages of discovery ended in shipwreck or ruin, yet they kept coming.
This hints at a population perhaps higher in trait Openness and moderate Risk-Taking. Northern Europeans also had cultural sanction for worldly vocations (the Protestant work ethic encouraged enterprise), whereas in other civilizations, social status was tied more to bureaucratic office or land ownership than merchant risk-taking.
Over generations, those cultural values could select for enterprising personalities.
When it comes to industriousness, consider working hours and productivity. There are notable contrasts: for instance, the average South Korean works many more hours per year than the average Nigerian.
Such differences are partly economic (need vs. opportunity) but also reflect work ethic norms. In international student assessments and surveys, East Asian students report more time spent on homework and studying than many of their Western or developing-world counterparts – aligning with a culture (and perhaps genes) of diligence.
The fruits are evident in technological competitiveness: countries like South Korea, Japan, and increasingly China have become innovation powerhouses (from electronics to automobiles to high-speed rail) within a few generations, catching up to the West.
Meanwhile, countries with abundant natural resources but less emphasis on human capital often lag in innovation (e.g. oil-rich Gulf states import technology, they don’t create it – their native populations, while wealthy from oil rents, produce few patents or scientific advances).
Aggregate genetics likely contributes to these patterns. A population’s distribution of personality types – from cautious conformists to daring innovators – will affect its creative output.
Diverse, high-IQ societies that also have a segment of risk-takers and visionaries will generate more breakthroughs (and also occasional turmoil) than societies where most people are either highly conformist or, conversely, impulsively risk-prone without discipline.
It is plausible that European populations, having experienced centuries of genetic mixing and competition among states, ended up with a favorable balance: enough divergent thinkers to spark innovation, enough conscientious people to implement ideas diligently, and enough cooperators to scale them up commercially.
Other populations might have more skewed distributions (e.g. too risk-averse and conformist, or too impulsive and present-oriented), which can stifle sustainable innovation.
To illustrate with data: national IQ again acts as a proxy, correlating not just with basic economic growth but with patents per capita and high-tech exports. But IQ alone isn’t destiny – as there are genetic traits beyond IQ that influence innovation.
Some high-IQ countries underperform in innovation due to rigid culture (perhaps Japan’s relative lack of Nobel prizes historically, despite very high IQ and strong economy, related to hierarchical conformity – though Japan has improved in recent decades).
Conversely, moderately high-IQ but extremely dynamic cultures, like the United States (a magnet for inventive personalities globally), lead in innovation.
The interaction of intelligence with creative personality and risk taking is key. Those traits all have genetic components that can differ among groups, meaning some populations are statistically predisposed to be more innovative.
Overall, traits driving exploration and industry – the “killer apps” of modernization – are unevenly distributed. The legacy of who took risks (sailing unknown seas or tinkering in workshops) and who worked doggedly (turning inventions into mass production) lives on in the genetic and cultural profiles of populations. Diamond attributed the differences in outcomes to accidents of geography, but an alternative view is that Eurasian peoples evolved under intense competition to become especially driven and innovative, whereas others in more isolated or stable settings had less impetus for disruptive innovation. Those differences help explain why it was Europeans who ended up with the “guns and steel” advantages – not simply because wheat grew in Europe, but because of who the Europeans had become after millennia of post-agricultural evolution.
V. Empirical Evidence: Genes, Traits, Societal Outcomes
Having qualitatively outlined how aggregate genetic differences can influence history, we now present concrete empirical comparisons to reinforce the case.
Across the world, we observe consistent patterns linking population traits to development outcomes, which defy explanations based on environment alone.
A.) Cross-National Comparisons of Traits & Outcomes
Let us compare a few countries on key metrics:
Sweden, Japan, and Singapore all have high average IQs and relatively high social trust, corresponding to high economic output and low corruption.
Brazil and Nigeria, with significantly lower average IQs and trust, have much poorer outcomes and rampant corruption.
While each country has its unique complexities, the overall pattern is clear.
High-IQ, high-trust populations (often East Asian or Western) have created prosperous, well-governed societies.
Low-IQ, low-trust populations (many tropical, resource-rich countries) struggle with poverty and corruption.
Geography cannot fully explain this: Nigeria and Singapore are both tropical and were both colonized by Britain, yet Singapore (mostly populated by Chinese and other East/South Asian groups) is an economic marvel, whereas Nigeria (populated by indigenous West Africans and extremely rich in oil) remains plagued by underdevelopment. The human factor is decisive. (A wealth of sorrow)
Even within the same geographic regions, we see stark contrasts that align with human capital. In the Americas, for instance, countries with higher proportions of European or East Asian descended populations (such as the United States, Canada, Chile) tend to have higher development and governance scores than those with mostly indigenous or African-descended populations in the tropics.
The differences persist despite similar climates or continent. Likewise, in Africa, countries with significant European or South Asian minority input (e.g. South Africa, Mauritius) have somewhat better economic outcomes than those without – albeit the pattern is complicated by colonial exploitation.
Nonetheless, whenever there is a “natural experiment” of different groups in the same environment, we often see outcomes align with the groups’ global patterns.
For example, ethnic Chinese diaspora communities in Southeast Asia (Malaysia, Indonesia, the Philippines) consistently outperform the local national averages in income and education, despite sharing the same country and geography.
They bring with them the human capital advantages of their ancestry. Such cases strongly indicate that who the people are matters, not just where they happen to live.
B.) Historical Selection Pressures & Founder Effects
Aggregate genetic traits today are the product of numerous historical selection pressures and migrations. By analyzing history through this lens, we gain insight into why populations differ.
“Survival of the Brightest” in Europe: Medieval and early modern Europe underwent what economist Gregory Clark called a “survival of the richest” – the upper classes had more surviving children, gradually spreading traits like diligence, literacy, and foresight into the general population. Furthermore, centuries of living in large, competitive nations (and frequent wars) may have culled more antisocial elements and rewarded group cooperation. By the time of the Enlightenment, the European population had possibly become more predisposed to commerce, innovation, and organized cooperation than in antiquity. This could explain Europe’s late surge (surpassing older civilizations). Similarly, in East Asia, a rigorous meritocratic civil service (in Imperial China) and intense competition for success could have genetically rewarded cognitive prowess and discipline.
Harsh Climates & High Latitudes: We discussed the “cold winters” hypothesis – that evolving in higher latitudes selected for planning and intelligence. The genetic evidence (IQ correlating with latitude/temperature) supports this. In addition, cold climates may have selected against traits that hinder group survival (such as extreme aggression or impulsivity) because cooperation and planning were so vital in winter. The result might be populations with calmer, more rule-abiding temperaments in the far north. Northern Europe and Northeast Asia, for instance, have relatively low violent crime rates and more reserved cultures compared to equatorial regions – a possible echo of ancient selection.
Disease & Dietary Pressures: In Africa and parts of South Asia, heavy disease burdens (malaria, sleeping sickness, etc.) and unreliable food due to climate could create a different selection regime – perhaps favoring traits like physical resilience and fertility over long-term intellectual output. Some hypothesize that higher pathogen levels in the tropics favored collectivist and authoritarian social structures (to control disease via conformity) but also might have reduced average cognitive development (due to factors like malnutrition or direct parasite effects on brain development). These environmental pressures can lead to genetic adaptation that isn’t favorable to modern economic growth (for instance, genes that maximize energy for immune function rather than brain development, if we oversimplify). Thus, ironically, the same environment that Diamond points to as a disadvantage (tropical diseases) could have biologically reinforced the disadvantage via evolutionary trade-offs.
Founder Effects in Colonization: The populations that colonized various regions often imparted lasting legacies. North America’s early European settlers were disproportionately religious dissenters, craftsmen, and risk-takers seeking a new life – arguably a self-selected group high in independence and initiative. Their descendants built a society that reflected those traits (e.g. strong civic culture, entrepreneurship). Latin America’s colonists, in contrast, were often conquistadors and fortune-seekers, or later, administered colonies with imported slave labor, leading to stratified societies. The genetic mélange (European, Native American, African) in Latin America, combined with the often extractive colonial institutions, resulted in populations with lower average education and trust than in the U.S. or Canada (which were settler colonies with families). These founder effects still show up in outcomes: compare the per capita GDP of Canada (settled by British/French families) to that of a resource-rich country like Venezuela (colonial stratification and later oil rent focus). Canada is far ahead despite Venezuela’s oil bonanza – owing to differences in human capital and institutions rooted in their colonial demographic histories.
Migratory Filtering: Migration itself can be an evolutionary force. Those who ventured out of Africa into challenging new environments tens of thousands of years ago might have been an adventurous, innovative subset of humanity. Some biogeographers have suggested that human populations farther from our African origin had to undergo multiple bottlenecks and challenges, potentially increasing selection for certain traits (though also losing some genetic diversity). The “self-domestication” of humans in different regions could thus produce varied temperaments. More recently, within the last few centuries, migrations like the European emigration to the New World or the Indian and Chinese diasporas overseas were not random samples of their home populations – they were often the more ambitious or desperate individuals willing to take risks. The accumulation of these effects means regions of settlement got populations with a particular drive that remained in their gene pool. This can partly explain why, even after accounting for institutions, countries like the USA, Canada, Australia (all of which had large immigrant settler inflows) are exceptionally high in measures of innovation and economic dynamism.
C.) When Resources Fail to Predict Prosperity
If Diamond’s environmental thesis were fully correct, we would expect resource-rich or geographically blessed areas to consistently outperform resource-poor ones.
In reality, we find many counterexamples where environment alone would predict the opposite of what occurred.
Resource Curse: Economists often talk about the “resource curse” – paradoxically, countries with abundant natural resources (oil, minerals) often have worse development outcomes (slower growth, more conflict) than those with fewer resources. Examples include oil-rich nations like Nigeria or Angola, mineral-rich countries like the DRC or Sierra Leone, and others. These places have every geographic reason to prosper (valuable commodities, arable land, etc.), yet they are mired in poverty and corruption. Why? The resource curse is fundamentally a human problem: poor governance, short-sighted exploitation, and conflict (all stemming from aggregate genetics). In high-IQ, high-trust countries, natural resources can be a boon (e.g. Norway manages oil wealth prudently); in low-IQ, low-trust countries, resources become a trigger for rent-seeking, theft, and civil strife. In Nigeria, for instance, decades of oil exports have yielded little broad improvement in living standards – instead fueling massive corruption. The traits of the society (lack of transparency, high corruption tolerance, limited technical know-how beyond the oil sector) explain this failure, not the physical environment.
Geographic “Sweet Spots” that Stayed Poor: Some regions had favorable geography but lagged. The Fertile Crescent of the Middle East had an early advantage in agriculture, yet today those regions (Iraq, Syria, etc.) are not leaders in prosperity – often due to conflict and governance issues. Large parts of South Asia (plains of India, for example) were fertile and supported huge populations, but technological progress there was slower than in smaller European nations. Many tropical islands with rich soils and biodiversity (like Haiti or much of the Caribbean) never developed advanced economies – often because the human capital (education, institutions) remained low. It wasn’t for lack of sun and rain that Haiti is impoverished while Singapore (a former malarial swamp with no resources) is wealthy; the difference lies in human factors – Singapore benefited from a high-skilled populace and strong social cohesion, whereas Haiti suffered from a legacy of slavery, low education, and institutional breakdown.
Rising Stars with Poor Geography: Conversely, look at countries that succeeded despite environmental limitations. Singapore, as mentioned, lacks natural resources and even had to import fresh water for years – yet it transformed into a global financial and trade hub thanks to its people (largely ethnic Chinese and Indian ancestry) and their work ethic and knowledge. Israel, a small country half-covered in desert, became a technological and agricultural innovator (e.g. drip irrigation, high-tech startups) due to a highly educated population and cultural drive. Even within Europe, take a country like Finland – far northern climate, short growing season, no great bounty of exportable resources – yet Finland is very prosperous with top-notch education and governance. These cases underscore that human capital can overcome environmental constraints. If environment were paramount, Singapore and Israel should not outperform oil-rich Iran or Venezuela, yet they do by a wide margin.
In all these comparisons, the theme is that population qualities reliably predict success or failure where geography does not. The avoidance of this conclusion in popular discourse is often due to discomfort: attributing inequality to external luck (guns, germs, steel) is more politically palatable than attributing it to internal differences among peoples. But as we see, the real world keeps contradicting the notion that environment is everything. Where environment predicts one outcome and human capital predicts another, the human capital tends to win out.
VI. Guns, Germs, Steel: Ideological & Political Implications
Diamond’s work became widely praised in part because it offered a narrative of global history that exculpates any notion of intrinsic group differences.
In the late 20th century, the idea that biological differences might underlie civilizational disparities had become taboo – associated with colonial racism or Nazism.
Diamond explicitly positioned his book against “racist” explanations, declaring them not only repugnant but factually wrong.
This stance, while morally well-intentioned, arguably veered into ideological comfort at the expense of empirical rigor.
The reluctance to discuss genetic differences led to a situation where environmental just-so stories filled the void.
It became politically correct orthodoxy to ascribe every inequality to geography, colonialism, or “structural” factors, and to vehemently deny any role of biology.
However, scientific findings (from psychometrics, behavior genetics, and evolutionary anthropology) increasingly undermine the extreme egalitarian assumption that all populations are identical blank slates.
Ignoring these findings can have several negative implications:
Misleading Narratives: By attributing the entirety of Eurasian dominance to latitude and luck, Diamond’s narrative overlooks the agency and attributes of the people themselves. This can border on a form of “deterministic pity” – implying that, for example, New Guineans or Native Americans never had a chance purely due to geography. Yet we know all humans have agency; societies have risen and fallen in complex ways. (I’d argue pseudo-agency here — as “agency” is downstream of genetics). A more balanced narrative would acknowledge that some populations developed advantageous traits (through evolutionary adaptation) and others did not, which is a less comforting story because it suggests not all groups were equally equipped. Clinging to the comfort of egalitarianism can thus distort historical understanding.
Policy Missteps: If one believes only environment/institutions matter, one might pour resources into, say, transferring technology or instituting new laws in developing countries, expecting them to perform like developed ones. When such efforts fail (as many foreign aid and nation-building projects have), policymakers are perplexed. Accounting for human capital realities (education levels, cognitive skills, cultural norms deeply rooted in psychology) leads to more realistic expectations and strategies – for instance, focusing on improving nutrition and education at the very basic level to raise human capital, rather than assuming a poor country can industrialize simply by importing machinery. The aversion to genetic explanations has perhaps led to over-optimistic development projects that ignore the slow, generational work of building human capital.
Stigmatizing Honest Discussion: The blanket rejection of any genetic component (as “loathsome,” to use Diamond’s word) means that researchers who do find evidence of biological differences are often ostracized or their work preemptively dismissed. This chills scientific inquiry. Important questions – such as how much of the poverty in some regions is due to low cognitive skill vs. due to external exploitation – deserve investigation, because the answers inform what solutions are viable. By labeling one answer racist and off-limits, the academic community may blind itself to truths that, while uncomfortable, could be key to solving problems. Indeed, Diamond’s own field, evolutionary biology, teaches that populations adapt to environments – it is ironic that he denied this principle when it comes to humans. Over the long run, politicizing science in this way erodes trust in expertise, as people eventually see the dissonance between official narratives and observable reality.
Moral Double Standards: Some critics point out that removing human agency cuts both ways – if success is just luck of geography, it denies credit to the achievements of societies as well. It’s a form of geographical determinism that, taken to extreme, minimizes the hard work and ingenuity of various cultures. A more nuanced approach recognizes both environmental and human contributions. Acknowledging genetic differences does not mean embracing crude racism or determinism; it can be simply recognizing that human biodiversity is part of our species’ story. By avoiding this topic out of fear, we leave it in the shadows where it can be misused by extremists, rather than addressed openly and scientifically.
In essence, the ideological taboo against genetic explanations led to the enthusiastic embrace of Diamond’s thesis in popular culture and academia. It provided a guilt-free and feel-good explanation for global inequality: “Nobody is inherently smarter or more hard-working; some just had better crops and animals.” Yet as we’ve shown, this comfort comes at the cost of truth. Real-world evidence strongly suggests that inherited traits do matter, and by not grappling with that, we risk crafting policies and narratives that are doomed to fail. Intellectual honesty – along with compassion – is needed to replace politically correct simplifications with empirically supported nuance.
VII. First-Principles Logic: Environment Isn’t Enough
Stepping back from the details, we can apply some first-principles logic to test the proposition “environment alone accounts for global inequality.” Several thought experiments and observations cast doubt on this idea.
A.) Same Environment, Different Outcomes
If environment were everything, then placing a given population in a new environment should fully determine their outcomes according to that environment.
But in practice, when people migrate, they often retain relative advantages or disadvantages.
For example, when Indians and Chinese migrated to East Africa and the Caribbean in the 19th–20th centuries, they (and their descendants) frequently became more economically successful than the native populations, despite sharing the same climate and local resources.
Their human capital – skills, education, perhaps cognitive traits – allowed them to thrive in an environment where others struggled.
Similarly, African-descended populations in North America (brought via slavery) have not converged to the same average outcomes as European-descended populations after centuries in the same environment, which suggests remaining differences (whether due to genetic or deeply ingrained cultural factors).
Environment cannot explain intra-society disparities that track along lines of ancestral population.
B.) Environmental Equalization
Over the last century, technology has greatly equalized many environmental factors across countries.
Global trade means any nation can import crops or goods it lacks; modern medicine means tropical diseases can be cured or prevented; knowledge flows faster than ever.
Yet despite this convergence of external factors, huge gaps remain in innovation, income, and governance. If anything, as some environmental gaps closed, the importance of human capital became more evident.
Countries like Japan or Korea that were once considered “geographically disadvantaged” (small land, few resources) raced ahead once given access to global markets – because their educated populations could take advantage of the opportunity.
Meanwhile, countries with oil wealth that gained independence and modern infrastructure sometimes regressed politically (e.g. Venezuela) when the wrong leaders or policies took hold.
The persistent divergence in outcomes in an increasingly flat world indicates that internal differences, not external, drive success in the long run.
C.) Complexity Breeds Complexity
Modern advanced societies are extraordinarily complex systems – they require millions of people to coordinate via implicit norms, contracts, and institutions.
Such complexity cannot be generated just by having fertile land or a large population. It arises from iterative problem-solving and trust-building over generations.
If one group of people has even a slightly higher average capacity to solve problems or cooperate, over hundreds of years that advantage can compound into a massive lead in societal complexity (much like a slightly higher interest rate yields huge differences in investment outcomes over time).
Thus small initial genetic differences in traits could lead to big civilizational differences – a possibility Diamond’s one-time geographic “head start” idea doesn’t fully capture.
Indeed, the world’s most powerful economies today are not those with the most arable land or best climate; they are those with the best human networks and innovation systems.
The ultimate resource is human ingenuity, and it appears some populations, for various reasons, managed to develop more of that resource.
D.) Out-of-Sample Tests
We can also ask: Do Diamond’s theories hold in situations he didn’t cover? For instance, Diamond emphasizes that Eurasia had more domesticable animals, which helped productivity and disease resistance.
But consider sub-Saharan Africa, which actually had one of the most important domesticable animals – the cow – and a suitable climate for it.
Cattle culture was widespread in Africa, yet it did not lead to an African equivalent of “guns and steel” that could resist European colonizers.
Or take the Americas: the vast Inca empire in the Andes had abundant crops and large populations; it collapsed to a small band of Spaniards, partly due to disease but also due to the Spaniards’ tactical and material superiority.
If geography were the sole determinant, one might expect the Incas to at least stalemate the invaders once initial shocks passed, but they did not – suggesting the invaders had a qualitative human capital edge (in military strategy, metalworking, sailing logistics, etc.) that was not merely bestowed by having horses.
These counterexamples imply something more at play than the orientation of continents or availability of species.
By reasoning from these fundamental angles, it becomes apparent that human factors must be in the equation. Geography and resources set the stage – they create opportunities or constraints – but how effectively a society exploits opportunities or overcomes constraints depends on the collective genetic traits of its people. Those traits themselves are mostly shaped by past environments (via evolution), creating a feedback loop that Diamond’s one-way environmental determinism fails to incorporate. Reality contradicts the notion that environment alone can explain global inequality; rather, environment interacted with human traits, and today, in a globally interconnected world, it is largely the human traits that differentiate outcomes.
Overall: Debunk of “Guns, Germs, and Steel”
Jared Diamond’s Guns, Germs, and Steel provided a socially convenient, politically-correct narrative attributing the fates of human societies to geographic and environmental luck.
While environment undoubtedly played an important role in early development, the theory of purely environmental determinism crumbles under scrutiny from the perspective of aggregate genetics and long-term human capital formation.
We have seen that:
Environmental advantages (good climate, domesticable plants/animals, absence of deadly germs) may give societies an initial boost, but they are neither necessary nor sufficient for sustained success. Human ingenuity and social organization increasingly became the determining factors as history progressed.
Populations differ in significant ways – average cognitive ability, personality traits, social trust, propensity for innovation – and these differences often align with historical and contemporary inequalities. High human-capital populations have consistently outperformed low human-capital ones, even in unpromising environments.
These population differences have logical origins in evolutionary history: different environments exerted different selection pressures over millennia, leading to biological (and cultural) adaptation. Diamond’s claim that basically only “environment matters” is ironically refuted by the evolutionary mechanism that environment creates biological differences. One cannot separate people from their environment in the long run; the two co-evolve.
Real-world data – from cross-country IQ and trust correlations with economic performance, to case studies of resource-rich failures and resource-poor triumphs – overwhelmingly support the view that human capital, broadly defined, governs development in the modern world. Countries that have tried to leapfrog via resources or institutions alone often falter if the underlying population capabilities are lacking.
Debunking Diamond’s core claims is not about denying the importance of farming or germs; it is about right-sizing their place in the story.
Guns, germs, and steel were proximate tools of conquest, but the ultimate tool was the human brain – and not all groups of humans had the same toolkit at their disposal, due to the disparate journeys of evolution and history.
Acknowledging this is crucial for a truthful account of history and for addressing the challenges of today’s global inequality.
It directs our attention to improving human capital – through nutrition, education, and perhaps embryo selection & gene editing – as the key to uplifting societies, rather than assuming any piece of technology or geographic fix will suffice.
The politically comfortable narrative offered by Diamond, where everyone’s potential was equal given the same environment, does not hold up to scientific scrutiny. Nature and nurture worked together to produce the mosaic of human societies, and differences in nature (i.e. genetics) are an inseparable part of that mosaic. Recognizing that is not a license for discrimination; it is a call to ground our understanding of human history and development in empirical reality, even if that reality is complex and sometimes uncomfortable. By doing so, we replace myth with truth and can then craft solutions that confront the world as it is – diverse in abilities and outcomes – and strive to enhance the flourishing of all human populations going forward.
My closing thoughts on Guns, Germs, and Steel…
Diamond’s core thesis in Guns, Germs, and Steel is inaccurate. It’s unclear whether he genuinely believes it, or if he simply recognized that a politically safe, socially palatable narrative — 'it was just geographic luck all along' — would sell more books and avoid controversy.
If Diamond were being intellectually honest, he’d admit that geography or environment only mattered to the extent that it sculpted population-level genetics via long-term evolutionary pressures.
So in that limited way, I actually agree with Diamond that geography mattered historically — but not for the reasons he highlights.
Geography mattered — but not because of crops, animals, or axes of diffusion in the simplistic way Diamond suggests. It mattered because it created consistent selection pressures over millennia that shaped population-level traits. The real driver wasn’t environmental luck. It was evolutionary luck.
Certain groups of humans evolved traits that were more adaptive for intelligence, cooperation, trust, long-term planning, stability, innovation — the stuff that scales civilizations.
These traits weren’t ‘chosen’ — they were selected over time through interaction between environment and behavior, with culture emerging as a reflection of those evolved traits — and later feeding back into the selection loop.
And here’s the key point: evolution itself isn’t a simple one-way process. It’s a feedback loop.
The environment shaped genetics, yes — but genetics also shaped the environment in return.
As certain traits emerged — like impulse control, future-orientation, or group cooperation — they altered culture, institutions, even selection pressures themselves. Norms emerged that promoted or punished certain behaviors.
Criminals may have been culled. Productive individuals may have had more reproductive success. Culture and society didn’t just reflect evolution — they fed back into it.
Even random events — disease outbreaks, famines, natural disasters — could exert bottlenecks or create weird selection pathways. But for any of that to result in lasting genetic change, it had to persist over centuries.
That’s why short-term environmental change doesn’t fundamentally reshape genetics — not unless it creates consistent selective pressure over many generations.
So no, it wasn’t just geographic luck that explains why some countries succeeded and others didn’t. It was the evolutionary trajectories of the populations living there.
Some groups evolved traits that allowed them to leverage their environments effectively — or even thrive despite geographic disadvantages.
Others, despite inhabiting “resource-rich” regions, lacked the aggregate traits to turn those into long-term civilizational advantage.
That’s why Diamond and I might both say “luck,” but I’m referring to evolutionary luck, not who got better land.
Now — this also explains why people misunderstand group differences within the U.S. as well.
When groups like Indians or Nigerians do well in the U.S., people often fail to consider that it’s usually a hyper-selected sliver of the population — the top 0.1% in intellect, education, or wealth — who make it here.
They do not represent the average genetic or behavioral profile of their home populations.
If you brought in the average person from those countries, the outcomes would be drastically different. So the “success” is often a reflection of elite selection bias.
Likewise, when people claim that certain groups “improve” after arriving in the U.S., it’s often due to better environmental conditions — improved nutrition, safety, education, healthcare — which improve brain development… but this doesn’t change underlying genetics (hence the persistent outcome gaps).
They’re simply expressing more of their potential. But again, these systems didn’t appear out of thin air — they were built and maintained by populations whose aggregate traits enabled them to do so.
The structures themselves are downstream of genetic evolution.
Modern institutions are not independent inventions — they are reflections of underlying trait distributions that made them both necessary and sustainable.
Genetic Evolution (over millennia):
Environment → selective pressures → genetic divergence by population (region, ethnicity, etc.) → emergence of aggregate traits → shaping of social structures, culture, norms → feedback into selection → continued divergence.
People can’t choose their race, ethnicity, or genome. Every group has intelligent individuals, but the distributions matter — the averages, the medians, the tails.
Some groups have fewer people in the extreme high end of the spectrum (and their “high end” isn’t as high). That has real consequences for innovation, institution-building, and long-term development.
So again, the mistake is in framing history and global achievement as a story of “environmental luck.” That’s a half-truth. The deeper reality is evolutionary luck.
The “winners” didn’t get lucky because of land — they got lucky because their ancestors evolved traits that proved highly adaptive in a modern, complex society. And once those traits emerged, they created a feedback loop — shaping institutions, social norms, and selective pressure — which kept reinforcing the advantage across generations.
None of this means that some groups are “better” or “worse.” Evolution doesn’t care about fairness.
A high IQ is considered “good” in 2025 because it’s adaptive now — but thousands of years ago, it may have conferred no survival advantage in certain environments (e.g. dense jungles, deserts, etc.).
Hence the reason it’s less common in some groups. Other traits — like endurance, acute perception, or environmental awareness — may have been more adaptive in those contexts.
Remember, it wasn’t necessarily “the fittest” or even “the most adaptable” who survived — it was often just those who were adaptive enough to pass on their genes.
The divergence we observe today wasn’t caused by geographic luck — but by the long-term interplay of evolutionary pressures, randomness, disease, trait divergence, and emergent culture — locked in a feedback loop that continues to shape societies today.