第 1 章
The Exodus That Shapes Our World
When Karl Hellenschmidt left poverty-stricken Germany for prosperous Bradford, England, he couldn't have imagined the xenophobic violence that would later destroy his family during World War I. His shop attacked, his wife nearly strangled, and himself interned as an "enemy alien," Karl's story mirrors countless immigrant experiences throughout history. His son, who would later become Charles Collier, was forced at age twelve to run the family business as his mother succumbed to depression. This personal history-shared by author Paul Collier, whose grandfather was that same young boy-frames a profound examination of modern migration. Named one of Bill Gates' five favorite books of 2019, "Exodus" has become required reading in policy circles from Brussels to Washington. Its influence extends beyond academia, with celebrities like Angelina Jolie citing its balanced approach in her humanitarian work. In a world where migration discourse has become toxically polarized, Collier offers something rare: a nuanced, evidence-based framework that acknowledges both the benefits and costs of the movement of people from the poorest societies to the rich West.
第 2 章
Breaking the Migration Taboo
Migration has become a subject so loaded with toxic associations that rational discussion seems almost impossible. In liberal circles particularly, it has become taboo-the only permissible opinion being to bemoan popular antipathy toward it. This taboo exists because migration has become confusingly entangled with attitudes toward poverty, nationalism, and racism. The mere mention of immigration controls often triggers accusations of xenophobia, while advocates for open borders are frequently dismissed as naive idealists, creating a polarized environment where nuanced discussion becomes nearly impossible.
Jonathan Haidt's research on moral psychology helps explain this polarization. People's moral values cluster into two broad groups: one emphasizing care and fairness, typically associated with liberal viewpoints, and another prioritizing loyalty, authority, and sanctity, more common among conservatives. These moral judgments shape our reasoning rather than the reverse-we grasp at reasons to legitimize judgments we've already made. This explains why migration debates generate more heat than light, with participants talking past each other using entirely different moral frameworks. For example, when confronted with statistics about economic benefits of immigration, those opposed often pivot to cultural concerns, while proponents might dismiss legitimate security concerns as mere prejudice.
The moral obligation to help the poor doesn't necessarily imply free movement across borders. Many effective poverty-reduction strategies, such as direct aid or trade policies, don't involve migration at all. Similarly, revulsion against nationalism, especially strong in post-war Europe, has led some intellectuals to reject borders entirely. This reaction, while understandable given historical traumas, often overlooks the practical functions borders serve in maintaining social cohesion and public services. Meanwhile, opposition to immigration often veers uncomfortably close to racism, which effectively shut down discussion in countries like Britain for decades. Only when large-scale Polish immigration occurred-which couldn't be attributed to racism-did the taboo begin to crack, allowing for more honest conversations about integration challenges and social impact.
What's needed is a clear-eyed analysis of migration's effects on three distinct groups: the migrants themselves, who often face both opportunities and significant hardships; the societies they leave behind, which may experience both brain drain and beneficial remittances; and the societies that receive them, which must balance economic benefits with social cohesion concerns. Only by understanding these complex dynamics can we move beyond simplistic positions toward policies that maximize benefits while minimizing harms for all involved. This requires acknowledging both the legitimate aspirations of migrants and the legitimate concerns of host communities, while rejecting both unrestricted movement and xenophobic fearmongering.
第 3 章
The Great Divergence and Migration's Acceleration
Why has migration from poor countries to rich ones accelerated so dramatically in recent decades? The answer lies in the unprecedented prosperity gap that emerged during the 20th century. For half a century after World War I, countries closed their borders as wars and economic depression made migration difficult and immigrants unwelcome. During this period of immobility, a dramatic economic gulf emerged between countries.
This prosperity gap stems from differences in social models-the combination of institutions, rules, norms, and organizations that shape economic outcomes. High-income societies have developed functional social models with effective institutions supported by productive narratives and social norms that enable cooperation and trust. In contrast, poor countries often have dysfunctional social models with weak institutions, counterproductive narratives, and norms that tolerate violence and discourage trust.
When workers move from poor countries to rich ones, their productivity dramatically increases because they switch social models. While ideas, goods, and capital can flow between countries as alternatives to migration, these processes are too slow to close the massive income gap within our lifetimes.
Migration operates through a multiplicative relationship-a wide income gap combined with a large diaspora and adequate income in origin countries creates substantial migration flows. Even when poorer countries grow faster than rich ones, the absolute income gap often widens for decades before eventually narrowing. Rising incomes in origin countries make migration more affordable, further accelerating flows.
Perhaps most importantly, migration produces diasporas, and diasporas facilitate more migration in a self-reinforcing cycle. Starting from 1960, when rich countries began reopening borders, initial migration was modest due to negligible diasporas. But as diasporas grew, migration accelerated.
For migration to stop accelerating, the diaspora would need to stop growing. This happens through "absorption"-the process by which immigrants and their descendants merge into mainstream society. The absorption rate depends inversely on diaspora size: larger diasporas slow absorption because members have proportionally fewer interactions with the indigenous population.
What does this mean for the future? With persistent income gaps and growing diasporas, migration from poor to rich countries will continue accelerating unless effectively managed. Data confirms this trend: migrants from poor to rich countries grew from under 20 million to over 60 million between 1960-2000, accelerating each decade. We're witnessing "the beginnings of disequilibrium of epic proportions."
第 4 章
How Diversity Affects Social Cohesion
The social consequences of migration depend critically on how rapidly immigrants integrate with indigenous society. While greater diversity brings beneficial variety, stimulus, and choice - from enriched cultural experiences to innovation in business and arts - it also creates complex challenges to mutual regard. This mutual regard represents the sympathy or benign fellow-feeling that supports two fundamental behaviors essential for successful societies to function effectively.
First, mutual regard underpins the willingness of successful people to finance transfers to the less fortunate through feelings of loyalty and solidarity. This manifests in support for welfare systems, progressive taxation, and charitable giving. In societies with strong mutual regard, citizens more readily accept higher tax rates to fund social programs, healthcare, and education for all members of society. Second, it enables cooperation in providing public goods that markets alone wouldn't supply well, such as infrastructure, environmental protection, and community services. This cooperation requires trust, which must be underpinned by the reasonable presumption that cooperative actions will be reciprocated-something mutual regard makes possible.
These cooperative outcomes are notably fragile. Trust and cooperation aren't primordial attributes but acquired attitudes that gradually accumulate in modern prosperous societies through generations of positive interactions and reliable institutions. Their absence helps explain why some societies remain poor despite abundant resources or strategic advantages. Studies of Africa demonstrate how lack of trust persists across generations: violent conflicts from before 1600 strongly correlate with modern conflicts, with distrust as the primary transmission mechanism across centuries.
Nigeria provides a stark example of a low-trust society where opportunistic behavior has become deeply ingrained. Hotels must meticulously check room contents before guests depart, and the life insurance industry effectively collapsed because death certificates could be purchased without actual deaths occurring. Similar patterns emerge in business transactions, government operations, and daily social interactions. Experimental games conducted across sixteen countries consistently confirm that in societies with weak rule of law, people are significantly more opportunistic, generally untrusting, and paradoxically more likely to punish those who enforce cooperation rather than the free riders themselves.
Migrants inevitably bring their cultural norms and trust attitudes with them to their new countries. Fisman and Miguel's influential study of UN diplomats' parking fine payments in New York showed behavior patterns strongly correlated with corruption levels in their home countries - diplomats from countries with high corruption were more likely to accumulate unpaid parking tickets. Similarly, attitudes toward social redistribution and welfare programs consistently reflect cultures of origin, often persisting into second and third generations.
Robert Putnam's groundbreaking research revealed that higher immigrant proportions in communities correlate with lower trust between immigrants and natives. More troublingly, immigration also reduced trust among natives themselves, leading to what he termed "hunkering down" - a phenomenon where natives retreat into themselves, participating less in social activities, having fewer friends, and watching more television. This effect was observed across various demographic groups and community sizes.
The benefits of greater variety through diversity are subject to diminishing returns, while the losses from reduced mutual regard may increase sharply as certain thresholds are crossed where cooperation becomes unstable. This suggests that moderate migration likely confers social benefits through cultural enrichment and economic dynamism, while sustained rapid migration risks substantial costs to social cohesion and cooperative behavior. The challenge lies in finding the optimal balance that maximizes the benefits of diversity while maintaining the social trust necessary for society to function effectively.
第 5 章
Multiculturalism vs. Integration: Competing Visions
Multiculturalism emerged as a reaction to assimilation, initially recognizing migrants' reluctance to abandon their cultures, but later reframed by liberal elites as inherently desirable. It has evolved into two distinct concepts: one envisions the permanent coexistence of separate cultural communities with equal status within a geopolitical space; the other promotes cultural fusion where migrants and indigenous populations blend their traditions.
Despite falling out of fashion, assimilation offers significant advantages. Ethically, it aligns with the golden rule of treating others as you wish to be treated, as few poor societies have successfully implemented cultural separatism. Learning the local language proves essential for participation in public goods provision and fostering mutual trust. Assimilation's practical consequences are benign: migrants absorb indigenous attitudes, develop mutual regard, and through intermarriage create common descendants, allowing immigrants to participate in the shared historical narrative of the society.
Cultural fusion similarly offers ethical soundness by affording equal dignity to migrants and indigenous people through creative blending, as exemplified by chicken tikka replacing fish-and-chips as Britain's most popular dish.
European political elites have embraced multiculturalism as persistent cultural separatism, legitimizing immigrant preferences for cultural isolation. This manifests in residential clustering and distinctive cultural practices, often tied to religious fundamentalism rather than host country policies. French second-generation Muslim immigrants show increasing religious strictness, while British Bangladeshi women adopt full veils not worn in Bangladesh itself-deliberately differentiating themselves from the indigenous population.
Political separatism follows, with countries of origin's political organizations re-forming in host countries. Tower Hamlets' local government faces feuding between Bangladesh's dominant political parties, while British Muslims created the Respect Party, winning parliamentary by-elections in immigrant-concentrated areas by appealing to voters based on identity.
Government policies significantly impact absorption rates. Multicultural policies that encourage distinct migrant cultures and networks slow integration, as Ruud Koopmans' research demonstrates. These policies lead to measurable effects: reduced aptitude in national languages, decreased willingness to cooperate in public goods provision, and increased spatial segregation. Generous welfare systems further slow integration by providing migrants accustomed to lower living standards with incomes that appear attractive enough to reduce job-seeking incentives.
The combination of multiculturalism for immigrants and anti-discrimination laws for indigenous populations creates a paradox: immigrants are encouraged to form tight-knit communities preserving their origin culture, while indigenous social networks must convert from "bonding" to "bridging" capital. This asymmetry violates the golden rule by treating groups differently.
第 6 章
The Economic Impacts: Winners and Losers
Economics provides two fundamental predictions about immigration's effects on host populations: worker immigration should reduce wages while increasing returns on capital-making indigenous workers worse off and indigenous wealth owners better off. Simultaneously, existing public infrastructure must be shared among more people, reducing per capita provision. Since poorer people derive more of their income from work rather than wealth and rely more heavily on government services, basic economic theory predicts immigration would disadvantage them most significantly.
Recent credible studies challenge these simplistic predictions. Research in Britain found that while wages at the bottom of the spectrum decreased as expected, wages increased along the rest of the spectrum, with most indigenous workers actually gaining from migration. Similarly, a European study found immigration increases indigenous wages because immigrants are often more skilled than native workers, complementing rather than competing with unskilled labor.
Housing impacts represent a more significant economic consequence than wage effects. Poor migrants with families compete directly with indigenous poor for social housing, creating substantial crowding-out effects in concentrated neighborhoods. The Office of Budgetary Responsibility estimates British house prices are approximately 10% higher due to migration-a regressive wealth transfer benefiting older, richer property owners. Paradoxically, these regional price disparities reduce internal mobility of indigenous workers, preventing them from accessing better-paying jobs in growth areas.
The demographic argument that immigrants are needed to offset aging populations proves unsustainable upon examination. Immigration provides only a temporary fiscal windfall while increased longevity continues indefinitely. Moreover, immigrants bring both children and parents, potentially increasing rather than decreasing dependency ratios.
While immigration can address specific skill shortages, it may ultimately weaken incentives to train indigenous workers. Britain's collapse in apprenticeship schemes coincided with rising immigration, with 80% of new jobs during peak years filled by immigrants. This reveals a divergence between business interests (cheaper recruitment of skilled migrants) and indigenous population interests (ensuring firms train local youth).
Within a standard economic model of migration, points systems create direct links between immigration and emigration by privileging relatives of existing diaspora. In a simplified three-country model, if Britain adopts open-door migration from Chad while America only accepts British citizens, the resulting wage pressures in Britain can drive British emigration to America. Immigration also amplifies boom-bust cycles, as seen in the 1997-2007 boom where immigration enabled both public and private overspending to continue without triggering inflation.
第 7 章
Migrants: The Primary Beneficiaries
Migrants are the primary economic beneficiaries of migration, experiencing productivity and wage gains that can be tenfold when moving from poor to rich countries. Studies using random visa lotteries and matched job comparisons demonstrate that these gains stem primarily from country characteristics rather than individual worker traits-the social models and institutions of wealthy nations enable dramatically higher productivity.
This explains why migrants "nation-shop" for destinations offering the best combination of wages and welfare systems that match their skill profiles, with lower-skilled migrants preferring more equitable European systems while higher-skilled migrants favor less redistributive economies.
Migration represents a significant investment with substantial upfront costs and gradual, risky returns. For people from poor countries earning under $2,000 annually, even airfare requires years of savings. Young people face the greatest financing challenges despite being ideal migrants. The investment is risky-failure brings both practical and psychological costs.
Unlike in wealthy nations, poor countries lack financial institutions for ordinary people, making family the only funding source. This creates two important patterns: selection by income (middle-income people migrate most as the poorest cannot afford it while the richest see little benefit) and family decision-making rather than individual choice. Families often finance migration in exchange for promised remittances, creating transnational family structures that mirror multinational companies.
Beyond financing challenges, would-be migrants face numerous barriers. Educational requirements serve as gatekeepers, with Australia and Canada imposing the most demanding standards. Family ties create another pathway, leading to strategic marriages where migrants become highly desirable spouses. When legal options fail, some resort to corruption, fraud, or dangerous illegal entry facilitated by people smugglers.
Diasporas serve as the dominant solution for would-be migrants, facilitating migration through multiple channels. Established migrants create legal pathways through family reunification privileges, provide crucial local information about opportunities, generate employment in their businesses, offer accommodation to newcomers, and facilitate financing for migration costs.
Surprisingly, migrants are also the big losers from migration in economic terms. While they don't compete directly with indigenous workers, migrants compete head-to-head with each other. Additional immigrants drive down the earnings of existing immigrants-the only clearly established substantial effect of immigration on wages.
Beyond economics, migrants face psychological costs from cultural dislocation and separation from family that may offset their income gains. Limited but rigorous studies suggest migrants experience no improvement in happiness or self-reported well-being despite substantial income increases. The second generation, however, may benefit without these psychological costs, suggesting migration follows the nineteenth-century narrative of sacrificing for children's opportunities.
第 8 章
Those Left Behind: The Forgotten Stakeholders
The impact of migration on those left behind in the poorest countries is a critical consideration in assessing migration's overall benefits and costs. For the bottom billion people living in countries with little hope of prosperity, migration's effects on social models will determine whether they escape poverty.
Migration's political impact on countries of origin is complex. Minorities disproportionately emigrate, which may either improve their bargaining power against discrimination or encourage repressive governments to adopt more discriminatory policies. Diasporas can be both assets and threats to home governments, providing safe havens for opposition, funding for political alternatives, and introducing democratic ideas.
The empirical evidence shows returning migrants bring back democratic norms and increase voter participation not just among themselves but among less-educated neighbors. The quality of the host country matters-France and the United States are better seedbeds of democratic values than Russia or African countries. Migration also transfers other functional social norms like smaller family size preferences.
Migration has direct economic effects on those left behind, particularly regarding education and talent development. While educated emigrants no longer contribute directly to their home countries, the opportunity for migration creates powerful incentives that may increase the overall stock of talent.
For families in poor countries, the prospect of migration makes education a priority despite its considerable costs. The better the chance of migrating, the bigger the payoff to education and effort. This creates two competing effects: a direct one that reduces talent through emigration and an indirect one that increases it through educational investment.
Studies show that when the initial exodus is large, especially in small countries, the talent loss cannot be recovered. Haiti has lost around 85% of its educated people, requiring a sevenfold increase in talent supply to offset-an impossible threshold to reach. Almost all small, poor countries end up as losers from migration, while large developing countries like China, India, and Brazil experience net gains.
Beyond education, migration affects productivity through worker motivation and organizational identification. The most work-positive individuals tend to emigrate, leaving behind fewer "insider" role models who internalize organizational objectives. Even if education levels increase due to migration incentives, productivity suffers when positive role models depart.
Remittances partially offset these losses. Migrants remain deeply connected to their families, sending substantial portions of their earnings home. Collectively, these transfers reached about $400 billion in 2012, nearly four times global aid flows. However, their importance varies dramatically by country. In Haiti, remittances constitute 15% of national income, in El Salvador 16%, and in Bangladesh and the Philippines 12%. For most African countries, the impact is smaller.
Remittances largely offset the lost output from emigration rather than providing substantial additional income. Studies show they serve as valuable insurance against local economic shocks, with migrants increasing transfers during crises. While remittances are not game-changers, they have helped relieve poverty in some of the poorest countries.
第 9 章
Toward Balanced Migration Policies
The evidence suggests a middle path between xenophobic fears and progressive open-borders advocacy. Migration to date hasn't significantly harmed indigenous populations, but without effective controls, it would accelerate rapidly, potentially harming host societies, countries of origin, and even migrants themselves.
Migration controls are ethically legitimate despite arguments from extreme libertarianism and universalist utilitarianism. Unrestricted migration could empty poor countries and radically transform host societies' identities. Societies have "existence value"-Mali should develop, not empty; England shouldn't become merely an extension of Bangladesh.
Left to decentralized decisions, migration naturally accelerates until low-income countries become substantially depopulated. Two factors drive this: larger diasporas make migration easier, and migration has minimal impact on closing the income gap between countries.
For host societies, migration creates economic and social trade-offs. Economically, moderate migration typically has slightly positive short-term wage effects, but accelerating migration would eventually drive wages lower and strain public services. Socially, diversity brings both benefits (fresh problem-solving perspectives, cultural variety) and costs (undermined mutual regard, cooperation, and willingness to redistribute).
A responsible policy package should prevent acceleration beyond the point where it harms both those left behind and host populations. Rather than waiting for policy panic, governments should adopt comprehensive approaches based on ceilings, selection, integration, and legalization.
Ceilings on migration serve both enlightened self-interest and compassion. Policy should distinguish between settlement migration (which grows the diaspora) and temporary educational migration (which benefits source countries without permanent diaspora growth).
After establishing migration ceilings, policy must address migrant composition across dimensions of household status, education, employability, cultural origins, and vulnerability. Family reunification rights should be limited proportionally to what indigenous citizens actually use. Education criteria are important as educated immigrants tend to raise indigenous wages, while less educated ones may lower them.
Controlling migration size and composition isn't the only way to manage diversity-increasing absorption rates also creates space within diasporas for new migrants. Effective integration strategies include cracking down on discrimination, requiring geographic dispersion of migrants, imposing school integration with ceilings on diaspora percentages, providing language learning resources, and promoting common citizenship symbols.
The polarized debate between social liberals wanting amnesty for illegal immigrants and conservatives fearing it rewards evasion has created policy deadlock. A balanced approach would maintain border controls but grant those who evade them guest worker status, permitting work and taxation without benefit entitlements, while creating a path to full legal status.
Mass international migration is a temporary response to extreme global inequality, not a permanent feature of globalization. As developing countries rapidly converge with high-income nations, migration will diminish over the coming century. One unambiguously positive legacy is that high-income societies have become multiracial, a profoundly liberating development. However, without effective migration policies, accelerating migration could lead to problematic outcomes: high-income countries might become postnational, multicultural societies with potentially undermined mutual regard, while small poor countries could suffer an exodus of talent beyond the point where emigration is beneficial.
