In Justice for Animals: Our Collective Responsibility (Simon & Schuster, Jan.), philosopher Nussbaum makes a case for animal rights.

What was wrong with previous approaches to animal rights?

They’re really not adequate to the complexity of animal lives. The Nonhuman Rights Project, a nonprofit animal rights organization, gives special attention to some creatures on the grounds that they’re very like humans. But you shouldn’t help animals and support their functioning because they’re like us, but because of them. The utilitarian approach of Peter Singer is a lot better, because it focuses on what we and other animals have in common, which is susceptibility to pain. But that’s not the only thing that matters—animals pursue many, many different things, including active, complicated social lives.

How is your approach different?

It goes all the way back to my doctoral dissertation on Aristotle’s treatise on animals. Aristotle thought that humans and animals have important things in common, namely perception and desire. For that reason, we should develop a common framework for thinking about both humans and other animals. That’s my starting point: why shouldn’t we think that, just as we pursue a rich range of complicated goals and it’s good for us to have many spaces open to us and protected for us, well, why not think the same way about animals—that they have diverse goals and are entitled to spaces for choice, and spaces for a flourishing life?

Could widespread animals rights come into conflict with each other, or with humans?

I think the right approach is to say that whenever a sentient being is stopped from living the life it wants to live, there’s wrong being done. And then the right question to ask is, how can we move beyond that? I worked for many years on Greek tragedy. Hegel believed that when there’s this clash of right with right, the essence of Greek tragedy, what we should do is think about a future in which that conflict would no longer be present. What would that look like?

How could you apply that to animal rights?

Medical experimentation is one area where I think there are urgent goals that are being pursued, and, of course, harm is being done to animals. So we can think—what would the world be like in which those important scientific goals could be reached without doing harm to any animals? Well, I think people already know there would be a world in which computer simulation does the job that’s now done by killing animals. And actually, experiments on rats are not very good predictors of human outcomes anyway. So that is a conflict that’s already on the way to being resolved. But it should happen more rapidly.