Ethical dilemma: Whose life is more valuable?

Smallpox is one of the deadliest diseases in history, but fortunately, it’s been eradicated for over 40 years. However, samples of the virus that causes smallpox still exist, leading to concern that rogue actors might try to weaponize it. This is especially worrying because older smallpox vaccines can have serious side effects, and modern antiviral drugs have never been tested against this disease. To protect against this potential threat, the US government is funding research to improve smallpox treatments and vaccines. And since it’s unethical to expose people to a highly lethal virus, labs are using humanity's closest biological relatives as research subjects. But is it right to harm these animals to protect humanity from a potential threat? Or should our closest relatives also be protected against lethal experiments? What would you do as a scientist faced with this very real scenario?

In many ways, this dilemma isn't new. Animals have been used in research aimed at improving human welfare for centuries, typically at the cost of their lives. This practice reflects the widespread belief that human lives are more valuable than non-human lives. People have different views about the ethics of animal testing and how it’s conducted. But whatever your opinion, this scenario raises an important philosophical question: how do we determine the value of a life, whether human or non-human? One tool philosopher has used to consider this question is moral status. Beings with moral status should have their needs and interests taken into consideration by those making decisions that impact them. Traditionally, moral status has been seen as binary— either a being’s interests matter for their own sake, or they don’t. And historically, many philosophers believed that humans had moral status and other animals didn’t.

Some contemporary philosophers like Shelly Kagan have argued that moral status comes in degrees, but even in this model, he argues that people have the most moral status. However, determining what grants any degree of moral status can be difficult. Enlightenment philosopher Immanuel Kant thought humans have moral status because of their rational nature and ability to will their actions. A binary conception of moral status then suggests that beings with these capacities are “persons” bearing full moral status, while all other creatures are “things” without moral status. But thinkers like Christine Korsgaard have argued a Kantian view should include many non-human animals because of how they value their own good. Another line of argument, suggested by utilitarianism’s founding father Jeremy Bentham and elaborated by Peter Singer, claims that a capacity for suffering makes an entity worthy of moral consideration.

These inclusive ways of thinking about moral status dramatically widen the scope of our moral responsibility, in ways some people might find unnerving. So where do our monkeys stand? Our closest genetic relatives have high social and intellectual capacities. They live cooperatively in complex social groups and recognize members of their community as individuals. They support and learn from one another— there’s even evidence they respond to inequality. And of course, they’re capable of suffering. Yet despite all this, it’s still generally common opinion that a human’s life is more valuable than a monkey’s. And that while killing one human to save five others is typically wrong, killing one monkey to save five humans is regrettable, but morally acceptable. Even morally required. At some point, however, this calculation starts to feel unstable. Should we kill 100 monkeys to save five people? How about 10,000? If moral status is binary and monkeys don't have it, then theoretically, any number of monkeys could be sacrificed to save just one person.

But if moral status comes in degrees and monkeys have any at all, then at some point the balance will tip. The situation you're in complicates things even further. Unlike the scenarios above, there's no guarantee your work will ever save human lives. This is true of any animal experiment— the process of scientific discovery only sometimes leads to improved medical care. But in your case, it’s even trickier! While the government is worried smallpox might be weaponized, if they’re wrong the disease will remain eradicated, and your research won’t save anyone from smallpox. You could try to quantify this uncertainty to help make your decision. But how do you determine what an acceptable amount of risk is? And what if there’s so much uncertainty that your calculations are essentially wild guesses? These kinds of moral mathematics get complicated fast, and some philosophers would argue they’re not even the best way to make moral decisions. But whatever you decide, your choice should be well justified.