What Do We Owe to People Who Can't Think Like Us?

A puzzle to start with

Imagine two beings. One is a human baby born with a condition called anencephaly—most of her brain is missing. She can breathe and her heart beats, but she will never be conscious, never feel pain or pleasure, never recognize a face or hear a voice. The other is a healthy adult chimpanzee. She can learn sign language, solve problems, remember people she hasn’t seen in years, and form deep bonds with others. She clearly has thoughts, feelings, and a sense of her own life.

Now here’s the hard question: which one is it more wrong to kill?

Most people would say it’s more wrong to kill the baby, even though the chimpanzee has more thinking ability. Most people would also say it’s more wrong to kill a human adult with severe cognitive disabilities than to kill a chimpanzee with greater mental capacities. But why? What is it about being human that makes our lives matter more—if it does?

This is the debate about moral status: who or what counts, morally speaking, and how much do they count? Are all human beings entitled to the same basic rights and protections simply because they’re human? Or does moral standing depend on what you can actually do with your mind—and if so, what about humans who can’t do very much?

Why This Is About “Radical” Disability

The philosophers in this debate aren’t arguing about people with mild or moderate intellectual disabilities. Almost everyone agrees that someone who can have friendships, make choices, understand fairness, or feel happy or sad has full moral status. The hard cases are people with what philosophers call radical cognitive disabilities—people who may never become conscious of themselves as having a past and future, who may never be able to reason about what to do, or who may never understand the idea of right and wrong.

Nobody knows for sure whether any actual human beings fall into this category. Some philosophers argue there probably are such people, because human development is gradual and some brains simply stop developing before certain capacities appear. Others say we can’t really know what’s going on inside another person’s mind, especially if they can’t communicate in ordinary ways. We might be mistaking a different kind of thinking for no thinking at all.

But to keep the debate clear, philosophers often say: let’s assume there are such people. The question then becomes: do they have the same moral status as you and me?

Two Ways of Answering

Broadly speaking, philosophers give two kinds of answers. One says moral status depends on what an individual is actually capable of. The other says it depends on belonging to a group—like the human species—that has certain characteristics.

The “You Are What You Can Do” View

This view starts with a simple idea: how much moral weight a being has should depend on what that being can actually experience, want, choose, and value. A rock doesn’t care what happens to it, so it has no moral status. A mouse can feel pain and pleasure, so it has some. A human adult can plan for the future, form deep relationships, and understand justice, so she has a lot.

But where does this leave people with radical cognitive disabilities? If moral status depends on things like being aware of yourself as a person with a past and future, or being able to reason about how to live, or being capable of moral responsibility—then some human beings may not have the same moral status as you or me.

This is a deeply uncomfortable conclusion. Most of us feel an instinctive horror at the idea of treating a human being the way we treat animals, even if that human being has fewer mental capacities than the animal. Philosophers who hold this view feel that horror too. They try to deal with it in a few ways:

Finding more inclusive capacities. Some philosophers argue that the relevant capacity isn’t rationality or self-awareness, but something simpler: the ability to care about things, or to form loving relationships, or to communicate at all. This would include more human beings. But it probably doesn’t include everyone—there may still be people who can’t care, can’t love, or can’t communicate in any recognizable way.

Proxy and presumption. Other philosophers suggest that people with radical disabilities can have full moral status through their relationships with others. A parent or friend can act as a “mental prosthesis,” helping the person form intentions and make choices they couldn’t make alone. Or we might simply presume that every human being has full moral status, because the cost of being wrong is so terrible—if we treat someone as less than human when they actually deserve full status, we’ve done something horrible. Better to err on the side of inclusion.

But these solutions have problems. Can someone else’s thinking really be your thinking? And if our presumption is just a practical rule to avoid mistakes, doesn’t that mean we’d drop it if we had better tests? That seems like a fragile foundation for human equality.

The “You Belong to a Group” View

The other major approach says: moral status isn’t about what you can do as an individual. It’s about what kind of being you are.

Species norms. One version of this view points out that human beings are characteristically rational and self-aware—that’s the normal condition of our species. Even if some individual humans don’t reach that norm, they still belong to a kind whose members normally have those capacities, and that’s enough. It would be like saying: a car that can’t run is still a car, and we treat it differently from a pile of scrap metal because of what cars are supposed to be.

Critics call this “moral alchemy”—trying to turn facts about one group of beings into moral status for another. Why should the capacities of typical humans rub off on atypical ones?

Ties of birth. Another version says: we are connected to other humans by bonds of kinship. We share the same origins, the same kind of body, the same kind of life. This gives us special reasons to care about each other—reasons we don’t have toward members of other species. A human with radical cognitive disabilities is still our fellow human, still part of our family. That’s why we owe them what we don’t owe a chimpanzee.

Critics say this sounds uncomfortably like racism or sexism—caring about people just because they’re like us. Supporters answer that species membership isn’t like race. We share a whole form of life with other humans: we eat the same way, express emotions the same way, grow up in families the same way. Those connections aren’t arbitrary.

The “humanity is a moral concept” view. The most radical version of the group view says that the very idea of a “human being” already contains moral obligations. When we learn what a human being is, we don’t first learn a biological fact and then figure out how to treat them. We learn that human beings are to be named, not eaten, cared for, not discarded. The concept itself shapes how we respond. So there’s no need to find some special attribute that “justifies” full moral status—it comes with recognizing someone as human.

This view is hard to argue against, because it says arguments don’t really work here. But it’s also hard to know what to do when we disagree about who counts as a human being. Does a human embryo count? Does a person with anencephaly? The concept of “human being” can’t answer those questions by itself.

Why This Debate Matters (and Won’t Go Away)

Philosophers are still arguing about all of this. There’s no settlement in sight.

Part of what makes the debate so hard is that both sides seem to capture something important. The individual-capacity view captures the idea that what matters morally is what beings can actually experience and suffer—that mere biology shouldn’t determine everything. The group-based view captures our conviction that every human being, no matter how disabled, deserves to be treated as one of us.

Neither side can fully explain why we feel the way we do about both animals and profoundly disabled humans. The individual-capacity view often seems to say that some humans count for less than many animals—which most people can’t accept. The group-based view often seems to say that being human matters more than anything else—which many people find arbitrary and species-biased.

The debate keeps going because the stakes are real. How we answer this question affects how we treat the most vulnerable human beings among us, how we think about abortion and end-of-life care, and how we understand our relationship to the other creatures we share this planet with. It’s not an abstract puzzle. It’s about who matters, and why.

Key Terms

Term	What it does in this debate
Moral status	A way of talking about who or what counts morally, and how much they count
Full moral status	The level of moral status that normal adult humans are thought to have—having rights that can’t be overridden easily
Radical cognitive disability	A label philosophers use for people who lack (or seem to lack) the mental capacities that might be needed for full moral status
Individual-based account	Any view that says moral status depends on what a being can actually do or experience
Group-based account	Any view that says moral status depends on belonging to a certain kind of group or species
Species norm	The idea that what’s normal for a species (like rationality for humans) can give moral status to all its members
Ties of birth	The idea that being born human creates a special moral bond between all humans

Key People

Peter Singer – An Australian philosopher who argues that moral status depends on the capacity to suffer and to have interests; he thinks some animals matter more than some humans, which has made him very controversial.
Eva Kittay – A philosopher and mother of a daughter with severe disabilities; she argues that relationships of care and love give all human beings full moral status, and that abstract theories often miss this.
Jeff McMahan – A philosopher who thinks moral status depends on individual capacities but tries to show that this doesn’t lead to treating disabled humans badly (he thinks our duties to them come from our relationships with them).
Corinne Diamond – A philosopher who argues that “human being” is not a biological label but a moral concept; learning what a human being is means learning how to treat them.

Things to Think About

If moral status really depends on individual capacities, then some animals (dolphins, chimpanzees, maybe elephants) might have more moral status than some humans. Does that seem right to you? If not, what’s your argument against it?
What makes “speciesism” (favoring humans just because they’re human) different from racism or sexism? Is it different? If it’s okay to favor your own species, what about favoring your own race or gender?
The “presumption” view says we should treat every human as having full moral status just to be safe. But does that mean we could treat them differently if we had perfect knowledge? Would knowing for sure that someone had no self-awareness or capacity for relationship change your moral obligations to them?
A chimpanzee and a human with anencephaly both lack the capacity for moral reasoning. Is there something that makes killing the human worse—or is it just a prejudice we’ve never examined?

Where This Shows Up

Disability rights activism – Disability advocates argue that theories of moral status have been used to justify discrimination, neglect, and even killing of people with disabilities. The debate is not just academic; it affects real policies about care, medical treatment, and legal protections.
Animal rights debates – The same questions about moral status come up when people argue about whether animals should have legal rights, whether factory farming is wrong, or whether we should keep animals in zoos.
End-of-life medicine – Doctors and families sometimes face decisions about whether to keep someone alive who has severe brain damage and will never regain consciousness. Different views about moral status lead to very different answers.
Abortion – The moral status of fetuses is one of the central questions in abortion debates, and the arguments are closely related to the ones about cognitive disability: does full moral status depend on what you can do, or on what kind of being you are?