Smallpox is one of the deadliest（致命的） diseases in history. But fortunately, it's been eradicated（根除） for over 40 years. However, samples of the virus that causes smallpox still exist, leading to concern（关心） that rogue actors might try to weaponize it. This is especially worrying because older smallpox vaccines（疫苗） can have serious side effects and modern antiviral drugs have never been tested against this disease. To protect against this potential（潜在的） threat（威胁）, the U.S. government is funding（投资） research to improve smallpox treatments and vaccines（疫苗）.

  And since it's unethical to expose（使暴露） people to a highly lethal（致命的） virus, labs are using humanity（人性）'s closest biological（生物的） relatives as research subjects. But is it right to harm（损害） these animals to protect humanity（人性） from this potential（潜在的） threat（威胁）? Or should our closest relatives also be protected against lethal experiments? What would you do as a scientist faced with this very real scenario（方案）? In many ways, this dilemma（进退两难的局面） isn't new. Animals have been used in research aimed at improving human welfare（幸福） for centuries, typically at the cost of their lives.

  This practice reflects the widespread（普遍的） belief that human lives are more valuable than non-human lives. People have different views about the ethics（伦理） of animal testing and how it's conducted（指挥）. But whatever your opinion, this scenario raises an important philosophical（哲学上的） question. How do we determine the value of a life, whether human or non-human? One tool philosophers（哲学家） have used to consider this question is moral（道德的） status（身份）. They believe moral status should have their needs and interests taken into consideration（考虑） 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（缘故） or they don't.