Mr. Sebo is the director of the animal studies program at New York University.
You might be aware that chimpanzees can recognize themselves in a mirror, communicate through sign language, pursue goals creatively and form long-lasting friendships. You might also think that these are the kinds of things that a person can do. However, you might not think of chimpanzees as persons.
The Nonhuman Rights Project does. Since 2013, the group has been working on behalf of two chimpanzees, Kiko and Tommy, currently being held in cages by their “owners” without the company of other chimpanzees. It is asking the courts to rule that Kiko and Tommy have the right to bodily liberty and to order their immediate release into a sanctuary where they can live out the rest of their lives with other chimpanzees.
The problem is that under current United States law, one is either a “person” or a “thing.” There is no third option. If you are a person, you have the capacity for rights, including the right to habeas corpus relief, which protects you from unlawful confinement. If you are a thing, you do not have the capacity for rights. And unfortunately, even though they are sensitive, intelligent, social beings, Kiko and Tommy are considered things under the law.
In response, the Nonhuman Rights Project is taking a bold position: It is arguing that if every being must be either a person or a thing, then Kiko and Tommy are persons, not things. I agree, and many other philosophers do, too.
In February, a group of philosophers, including me, submitted an amicus curiae brief to the New York Court of Appeals in support of legal personhood for Kiko and Tommy. (Members of the group contributed to this article as well.) The court is considering whether to allow the case to proceed.
The idea of nonhuman personhood might seem confusing at first, since we tend to use the terms “human” and “person” interchangeably. But they are not equivalent. “Human” is best understood as a biological concept that refers, at present, to a member of a particular species, Homo sapiens. In contrast, “person” is best understood as a moral and legal concept that refers to an individual who can hold moral and legal rights.
The question, then, is: If “human” and “person” are not interchangeable, why might someone think that only humans can be persons?
One view is that only humans can be persons because humanity is the basis of personhood. However, this view is implausible. There is nothing special about species in and of themselves. They are morally arbitrary taxonomic categories. There is a great deal of variability within species, similarity among species and change in species over time.
When we think about the basis of our own personhood, we do not think about how we happen to be classified in a biology textbook. Instead, we think about features of our lives such as conscious experience, emotionality, a sense of self and bonds of care and interdependence. When it comes to whether one should be treated as a person or a thing, these kinds of features, and not their genetic bases or evolutionary histories, are what matter. This is why we can all know that we have rights without having to check our genes.
Another view is that only humans can be persons because only humans have the ability to use language and reason in abstract and sophisticated ways. Kiko and Tommy can do many impressive things, including communicate with others and pursue goals in a creative, intelligent manner. But they cannot do these things in the same kinds of ways that many humans can.
However, this view of personhood is unacceptably exclusionary. We all lack the ability to use language and reason in abstract and sophisticated ways early in life, some of us lose these abilities later in life, and some of us never develop them. Yet while humans might not have moral or legal duties when we lack these abilities, we can clearly still have moral and legal rights. This is why many judges and legal experts now rightly reject this exclusionary view of personhood as fundamentally at odds with contemporary standards of human rights.
But now suppose we accept a more inclusive view of personhood, according to which humans are persons because we have some or all of the features mentioned before: conscious experience, emotionality, a sense of self or bonds of care or interdependence. This view is more plausible than the opposing view, in part because it includes all humans within the scope of personhood. At the same time, it includes some nonhumans too. For example, Kiko and Tommy are conscious, emotional, intelligent, social beings whose lives are deeply entangled with our own, their current state of isolation notwithstanding. As a result, they count as persons on any view inclusive enough to meet contemporary standards of human rights.
The idea of nonhuman personhood does raise difficult questions. One question is which rights nonhumans can have. For instance, if Kiko and Tommy can have the right to liberty, can they also have the right to property? What about the right to free expression or association, or the right to political representation or participation?
Another question is which nonhumans can have rights. For instance, if Kiko and Tommy can have rights, can bonobos and gorillas have rights too? What about cats, dogs and fish? What about chickens, cows and pigs? What about ants or sophisticated artificial intelligence programs?
These questions are unsettling. They are also reasonable to ask. After all, we might think that we need to draw the line somewhere. So if we decide not to draw the line at species membership — if we decide to accept that at least some nonhumans can have at least some rights — then it is not immediately clear where to draw it instead, or even, on reflection, whether to draw this particular kind of line at all.
However, it is important to keep two points in mind. First, the fact that a question is unsettling is not a justification for avoiding it. We should not ignore injustice out of fear of what it might mean to recognize it.
Second, the fact that a question is reasonable is not a justification for doubling down on our current answer. Some lines need to be either redrawn or eliminated. The history of human rights struggles (to say nothing of contemporary human rights struggles) is evidence enough of that.
Sometimes when we are overwhelmed by the complexity of an issue, it can help to start by stating a simple truth and going from there. In this case, the simple truth is that Kiko and Tommy are not mere things. Whatever else we say about the nature and limits of moral and legal personhood, we should be willing to say at least that. The only alternative is to continue to accept an arbitrary and exclusionary view about what it takes to merit moral and legal recognition. Kiko and Tommy deserve better than that, and so do the rest of us.