Getty Images; Illustration by Kirsten Salyer for TIME
November 18, 2015

Is everyone else a mindless zombie?

Maybe. Even your mother could be a zombie. She may not eat brains, but she could still be a philosophical zombie—someone who speaks and acts normally, but who lacks a mind. Think of a Stepford wife or pre-programmed android. If mom was this kind of zombie, she would still laugh and cry, but without real feelings behind her lying eyes.

Questions of zombie mothers may seem absurd, but they highlight a very deep truth—that other minds are ultimately inaccessible. Just as you can’t know if your “yellow” is actually my “blue,” you can’t know whether I even have a mind. This uncertainly may seem undisturbing, as you can be reasonably sure that your spouse and your boss—and even your mom—have minds. But what about a cow, or a corporation, or a computer? Do they belong in the “mind club” with you?

Questions of membership in the mind club are immensely important. In fact, belonging in the mind club is what makes us human. With a mind comes personhood and moral status. Without a mind, you are merely a “thing” to be bought and sold. Historically, people justified slavery by claiming that Africans had inferior minds. More recently, the practices of factory farming have been defended by seeing animals as mindless biological machines.

Our research reveals that whether something can think or feel is mostly a matter of perception, which can lead to bizarre reversals. Objectively speaking, humans are smarter than cats, and yet people treat their pets like people and the homeless like objects. Objectively speaking, pigs are smarter than baby seals, but people will scream about seal clubbing while eating a BLT.

That minds are perceived spells trouble for political harmony. When people see minds differently in chickens, fetuses, and enemy combatants, it leads to conflicts about vegetarianism, abortion, and torture. Despite facilitating these debates, mind perception can make our moral opponents seem more humans and less monstrous. With abortion, both liberals and conservatives agree that killing babies is immoral, and disagree only about whether a fetus is a baby or a mass of mindless cells.

Even minds are never completely objective, since new scientific tests can help to shape our perceptions and resolve disagreements. Consider the case of a 23 year-old-woman who had been in a vegetative state for 5 months following a car accident. Was her mind gone? Should she be removed from life support? These are questions that can spark firestorms of controversy.

To provide some guidance, neuroscientist Adrian Owens scanned the woman’s brain while asking her to imagine playing tennis or navigating through her house. When asked to imagine play tennis, her motor cortex fired, and when asked to imagine navigating, navigation-related brain regions. If this woman could consciously follow directions, then it seems that she did have a mind and therefore deserves moral consideration.

Not all issues of mind perception are resolved by technology. In many cases, apathy and hatred blinds people to the thoughts and feelings of others. Even without brain scans, it’s clear that Syrian refugees and illegal immigrants have minds, but we often fail to see their suffering because it would be emotionally taxing or inconvenient. Of course, empathizing with thoughts of the downtrodden or the feelings of our enemy can be difficult. But it might be worth trying, if only to reveal the presence of your own mind. After all, to others it might be you who seems like a zombie.

Gray is the author of The Mind Club

Contact us at editors@time.com.

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