In 2024, an association of female senior citizens in Switzerland won a case at the European Court of Human Rights. Their country, the women contended, needed to do more to protect them from climate change, since heat waves can make the elderly particularly vulnerable. The court ruled in favor of the group, saying that states belonging to the Council of Europe have a “positive obligation” to protect citizens from “serious adverse effects of climate change on lives, health, well-being, and quality of life.”

The exact policy implications of such rulings can be hard to assess. But there are still subtle civic implications related to the ruling that bear consideration.

For one thing, although the case was brought by a particular special-interest association, its impact could benefit everyone in society. Yet the people in the group had not always belonged to it and are not wholly defined by being part of it. In a sense, while the senior-citizen association brought the case as a minority group of sorts, being a senior citizen is not the sole identity marker of the people in it.

These kinds of situations underline the complexity of interest-group dynamics as they engage with legal and political systems. Much public discourse on particularistic groups focuses on them as seemingly fixed entities with clear definitions, but being a member of a minority group is not a static thing.

“What I want to insist on is that it’s not like an absolute property. It’s a dynamic,” says MIT Professor Bruno Perreau. “It is both a complex situation and a mobile situation. You can be a member of a minority group vis-à-vis one category and not another.”

Now Perreau explores these dynamics in a book, “Spheres of Injustice,” published this year by the MIT Press. Perreau is the Cynthia L. Reed Professor of French Studies and Language in MIT’s Literature program. The French-language edition of the book was published in 2023.

Around the world, Perreau observes, much of the political contestation over interest-group politics and policies to protect minorities arrives at a similar tension point: Policies or legal rulings are sometimes crafted to redress problems, but when political conditions shift, those same policies can be discarded with claims that they themselves are unfair. In many places, this dynamic has become familiar through the contestation of policies regarding ethnic identity, gender, sexual orientation, and more.

But this is not the only paradigm of minority group politics. One aim of Perreau’s book is to add breadth to the subject, grounded in the empirical realities people experience.

After all, when it comes to being regarded as a member of a minority group, “in a given situation, some people will claim this label for themselves, whereas others will reject it,” Perreau writes. “Some consider this piece of their identity to be fundamental; others regard it as secondary. … The work of defining it is the very locus of its power.”

“Spheres of Injustice” both lays out that complexity and seeks to find ways to rethink group-oriented politics as part of an expansion of rights generally. The book arises partly out of previous work Perreau has published, often concerning France. It also developed partly in response to Perreau thinking about how rights might evolve in a time of climate change. But it arrived at its exact form as a rethinking of “Spheres of Justice,” a prominent 1980s text by political philosopher Michael Walzer.

Instead of there being a single mechanism through which justice could be applied throughout society, Walzer contended, there are many spheres of life, and the meaning of justice depends on where it is being applied.

“Because of the complexities of social relations, inequalities are impossible to fully erase,” Perreau says. “Even in the act of trying to resist an injustice, we may create other forms of injustice. Inequality is unavoidable, but his [Walzer’s] goal is to reduce injustice to the minimum, in the form of little inequalities that do not matter that much.”

Walzer’s work, however, never grapples with the kinds of political dynamics in which minority groups try to establish rights. To be clear, Perreau notes, in some cases the categorization as a minority is foisted upon people, and in other cases, it is developed by the group itself. In either case, he thinks we should consider how complex the formation and activities of the group may be.

As another example, consider that while disability rights are a contested issue in some countries and ignored in others, they also involve fluidity in terms of who advocates and benefits from them. Imagine, Perreau says, you break a leg. Temporarily, he says, “you experience a little bit of what people with a permanent disability experience.” If you lobby, for, say, better school building access or better transit access, you could be helping kids, the elderly, families with kids, and more — including people and groups not styling themselves as part of a disability-rights movement.

“One goal of the book is to enhance awareness about the virtuous circle that can emerge from this kind of minority politics,” Perreau says. “It’s often regarded by many privileged people as a protection that removes something from them. But that’s not the case.”

Indeed, the politics Perreau envisions in “Spheres of Injustice” have an alternate framework, in which developing rights for some better protects others, to the point where minority rights translate into universal rights. That is not, again, meant to minimize the experience of core members of a group that has been discriminated against, but to encourage thinking about how solidifying rights for a particular group overlaps with the greater expansion of rights generally.

“I’m walking a fine line between different perspectives on what it means to belong,” Perreau says. “But this is indispensable today.”

Indeed, due to the senior citizens in Switzerland, he notes, “There will be better rights in Europe. Politics is not just a matter of diplomacy and majority decision-making. Sharing a complex world means drawing on the minority parts of our lives because it is these parts that most fundamentally connect us to others, intentionally or unintentionally. Thinking in these terms today is an essential civic virtue.”