a higher education level among the remaining population. This phenomenon is called brain gain, though to what extent the phenomenon exists in certain countries and particular sectors also varies considerably. Skilled emigrant diaspora populations can also contribute positively through remittances and political and economic channels. In addition, returning migrants can bring with them capital and progressive ideas that can help reform the local economy and advance more democratic regimes through changes in political climate and public opinion. Whether or not these effects have measurable impacts and whether they outweigh several categories of disadvantages of migration, such as reduced health outcomes, declining wages, weakened institutions, or increased political instability, is another important issue. Such topics are discussed in more detail elsewhere in the book, such as in chapter 8.
1.3 Is the contemporary state of affairs unique? Some history
The history of human migration is vast, complex, and fascinating. Here there is space to highlight only a few seminal migration moments from that history.
Humans have been moving about our planet since the origin of our species, as people began occupying all the regions of our world (Scarre 2013a). Homo erectus began moving out of Africa across Eurasia about 1.75 million years ago (Mithen 1996). Homo sapiens occupied Africa about 150,000 years ago and had spread to all habitable parts of Australia, Asia, and Europe by 40,000 years ago (Dunbar 2004; Scarre 2013a). Many factors motivated early humans to migrate, including climate change and the search for more adequate food supplies.
Since the Neolithic period (roughly 12,000 years ago), most migrations involved aggression, such as conquest and colonization (Scarre 2013a). Colonialism, which began intensifying about 500 years ago, involved the expansion of settled populations, largely from Europe. European colonialism accelerated the pace of migration. New settlers sometimes overwhelmed and virtually eradicated local populations.
There has been much human migration related to colonial and postcolonial events, war, slavery, religious pursuits, persecution, and economic goals (Fisher 2014). I obviously cannot cover all these cases in any detail, though I certainly will make reference to relevant features of this history in the chapters to come. For instance, several theorists draw on aspects of colonial history in arguing for reparative duties or other justice obligations towards those peoples who were previously colonized or significantly disadvantaged by historical processes.
Here I pick out only a few examples to give a flavor of some of the large-scale migrations that have taken place. Often migration has been driven by tensions and has in turn been the source of further tensions. Migration can also be a way to connect diverse communities across the world and to promote mutually beneficial goals. I have chosen a few instances to illustrate how there have been several common reasons for movement across the centuries. Dominant among these reasons are two: first, attempting to escape conflict, persecution, or violence; and, second, seeking better economic, social, or political opportunities for oneself and one’s family.
During the world wars and their aftermath, there was considerable movement, with millions motivated to avoid genocide, conflict, and hostilities. The Potsdam Agreement, signed in 1945, gave rise to the largest migration in the twentieth century in which approximately 20 million people were resettled; 16.5 million Germans were expelled from Eastern Europe, but so were hundreds of thousands of Poles, Ukrainians, Lithuanians, and Belarusians. Many Jews from Eastern Europe also migrated to countries such as Israel and the United States.
The aftermath of World War II also heralded a move for colonized states to seek separation from their former colonists. A wave of new independent states gave rise to much tension which necessitated large-scale movement. The partition of India offers one of the most dramatic examples. In 1947, huge populations of Hindus, Sikhs, and Muslims moved either away from or into the newly created state of Pakistan. The partition displaced approximately 17 million people.
The term “the Great Migration” is often used with reference to the movement of African Americans from the rural Southern United States to the Northeast, Midwest and West between 1910 and 1929. At that time, African Americans faced extensive political and social barriers to advancement, especially economically. The regions to which they migrated offered vastly different economic, social, and political prospects. A second wave of migration, called “the Second Great Migration,” took place from 1929 to 1970, when opportunities began to change in the South. About seven million African Americans migrated in these so-called Great Migrations.
As this very brief historical synopsis illustrates, our species, Homo sapiens, has always migrated; indeed, the history of human beings centrally involves migration. However, the issues concerning human movement that we face today are more complex and multifaceted than ever before. Like our forebears, central reasons for migration involve the quest for new opportunities, scarcity of resources, environmental challenges, religious persecution, ethnic tensions, wars, or unstable post-conflict societies. At various periods in our history, technological change facilitated and multiplied movement opportunities, and this is clearly evident in our current stage of globalization, in which vast numbers of people are able to travel as never before. The higher density and efficiency of transportation, along with superior technological and communication linkages, make global travel and migration much easier today than it was centuries ago. That swiftness and efficiency of transportation can be an advantage when it moves people rapidly to the opportunities they seek. But it can also prove to be a massive disadvantage, notably when it allows disease to spread at a record pace. In chapter 9, I discuss just how the current tragedy of Covid-19 is affecting migration and is likely to influence migration debates in the future.
1.4 Overview of subsequent chapters
Chapter 2 discusses issues related to states’ rights to exclude others and whether borders should be more open than they currently are. The surge in attention to migration in mainstream political theorizing began with two especially important works, which present the seminal arguments of two seemingly opposed positions. These two works have shaped contemporary theorizing about migration like no other and they therefore deserve extended treatment. Michael Walzer (1983) defends the right of states to limit migration and, in response, Joseph Carens (1987) argues for generally open borders. These two works in particular mark the beginning of an explosion in theorizing about migration problems. The right to control admissions raises issues about the nature of political communities and national identity, which can connect closely to people’s sense of personal identity and values. It also invites us to think about whether national identity has a role to play in sustaining democracies, the legitimate scope for self-determination, rightful authority to exclude from a territory, just and unjust occupation, settlement, and land use. These topics are introduced in this chapter and weave through several others as well. Many prominent theorists have weighed in on these issues and some of the most influential positions are covered in this chapter.
In chapter 3, I discuss our responsibilities in relation to forced migration. Much migration is forced, as in the case of refugees. What responsibilities do we have to refugees seeking safe haven? Granting asylum, offering resettlement, and facilitating repatriation are just some options to consider. What grounds any obligations we have to refugees? And what would it mean for a state to do its fair share, given that more than 70 million people are currently displaced by conflict at home? In this chapter, some prominent answers to these questions are considered, including those of Michael Walzer, Joseph Carens, David Miller, David Owen, Mathew Gibney, Alexander Betts, and Paul Collier, analyzing their strengths and weaknesses. We also cover some contemporary developments concerning how to assist refugees effectively that address many needs, along with the unique solutions that consideration of climate change refugees might require.
In chapter 4,