theories, different as they are, would all converge on justifying the same conclusion, namely that the position of open borders is the most defensible. This convergence is strong evidence for the view that we should open our borders. In what follows, I pick out just a few of the many ideas he offers to illustrate how this convergence strategy works.
On a libertarian theory, in which liberty is weighted as the most important value, individuals have the right to enter into voluntary activities and exchanges with other individuals. The state should not interfere with such freedom-enhancing exchanges and activities, provided such activities do not violate others’ rights. So, if a farmer from the United States of America wishes to hire a worker from Mexico, the government should not interfere, which it essentially does by blocking such exchanges when it controls immigration policy. The government’s restricting such an exchange would violate the rights of both the US farmer and the Mexican worker to engage in mutually beneficial voluntary transactions.
On a utilitarian account, in which we aim to maximize the good consequences for all affected by a decision, again an open borders position is most justified, according to Carens. If we considered the economic gains and losses for all affected, and especially the situation of the approximately one billion people who currently live in a situation precariously close to one of poverty, it is plausible to reason towards the conclusion that the wellbeing of more people would be enhanced were we to allow more of the disadvantaged from low-income countries to move to higher-income ones, where economic opportunities are more abundant and levels of income far higher. (I continue to discuss other utilitarian considerations elsewhere in this book, such as below in section 2.4.)
And on the Rawlsian contention, Carens argues that people would choose open borders if they were in Rawls’s famous choosing situation. In the original position, the veil of ignorance shields us from knowledge that might bias our judgments about fairness. Such distorting information might include state of residence, level of affluence or economic development, population size or other demographic features. If we knew nothing about our situation in the actual world, we would choose open borders. An open-bordered world would maximize our freedoms and opportunities. Indeed, such a world would be most consistent with commitments to freedom and equality of opportunity.
The importance of freedom of movement in securing other freedoms Another key strand of Carens’s seminal argument is the importance of freedom of movement in securing many of our other freedoms. Protecting at least some core freedoms is essential for a valuable life. Among those basic freedoms is freedom of movement. These basic freedoms are not only intrinsically valuable but also instrumentally valuable in that they protect other freedoms. The same issues that motivate concern for freedom of movement within the state also drive concern for freedom of movement across borders. The only way in which such an argument could be challenged is if constraining this freedom were important for protecting other basic liberties. And this is a point that Carens also entertains and mostly rejects. So while threats to public order or security may constitute legitimate grounds for limiting liberty, this is so rarely genuinely the case that it does not make much of a dent in the general view that concern for freedom should translate into a general willingness to open borders.
We turn next to some other arguments in favor of open borders offered by other prominent theorists.
2.2.2 Freedom (again)
Many theorists have developed all of the main themes we find in Carens’s influential arguments. Let’s start with the argument from concern for freedom. We see how authors have significantly developed this line of argument in ways that both support and challenge Carens’s original line of argument.
There are many freedom-centered arguments for open borders. These often start from the premise that in order for people to pursue their life plans, they must be able to cross borders. For instance, to pursue religious, cultural, or career goals, one needs the freedom to move to where these opportunities can be enjoyed, if they cannot be pursued within the bounds of a person’s state (Carens 1987; Cole 2000; Oberman 2013).
But there are challenges to this line of argument. David Miller argues that freedom does not require completely open borders and unlimited options. Rather, if there is a sufficient range of options, crossing borders cannot be justified using such arguments (Miller 2005, 2007). Freedom of movement should be a basic liberty because of the ways in which it protects individuals’ freedoms to pursue life projects from an adequate range of valuable options. When our state of residence provides these options, our freedom of movement cannot justify the freedom to cross borders (Miller 2005, 2007). Of course, many of those who would like to cross borders do so precisely because their states fail to provide the relevant options, so this argument may not be sufficient to block much real-world migration.
To illustrate some different concerns related to freedom, consider the libertarian argument that Carens introduces. The libertarian version of the argument often starts with claims about the importance of associational freedom or freedom to contract. Suppose a farmer in Arizona needs workers and someone from Mexico is prepared to do this work. If the state prohibits the farmer from contracting with the Mexican worker, it is interfering with the free choices of consenting adults and also violating their freedom to contract. Is the libertarian argument persuasive?
Insofar as the arrangements impose costs on others not party to the transaction, those negatively affected might reasonably complain. Some costs may not be germane – the freedom to be protected from competition might be one (Carens 1987). But others might be relevant. Insofar as such arrangements put downward pressure on compatriots’ wages, such that they can no longer meet their basic needs, such situations could be relevant to whether the transaction is permissible, someone might argue (e.g. Song 2019).
Similarly, freedom of movement across borders might be constrained by parallel reasoning. Some may be concerned that high numbers of migrants will affect a state’s capacities to maintain security or protect civil rights. Some also worry that large numbers of culturally diverse immigrants would also present integration challenges and threaten civil liberties (Kymlicka 2001). Authors have different assessments of the level of immigration that could be supported that avoids these effects, and here empirical considerations are certainly relevant. Empirical evidence across countries varies greatly and so might well support different conclusions for particular contexts. We return to some of these themes in later chapters (such as chapters 4, 5, 7 and 8).
2.2.3 Concerns of global justice and inequality
Our world is filled with very high levels of inequality and poverty on a global scale. And so, on this argument, states have duties to open their borders to the global poor. Failure to do so entrenches inequality and global poverty.
Many challenges can be marshaled to such a view. One important challenge concerns debates around this question: Is migration an effective means for addressing global poverty? This depends on what you believe effectively addresses global poverty (an issue we consider in more detail in chapter 8) and with what kinds of alternatives you are comparing migration. Many believe that foreign aid is an effective solution. You might have the view that migration can be more effective than foreign aid in some circumstances, for instance when there are high levels of corruption, incompetence in aid distribution, or aid is otherwise ineffective. Or you might have the view that opening borders does not help those most in need since those who migrate are often the more advantaged of the disadvantaged, having (for instance) sufficient resources to make the trip.
Indeed, you might believe that
