Imagine the following scenario: your little sister needs an organ transplant, and you are a match. The surgery would save her life, but there is a high probability of your own death. What would you do?

Now imagine this one: you are a pregnant woman, and you have just learned that you have cancer. You could go through chemotherapy and radiation which would save your life but kill the baby, or you could forgo treatment, carry the baby to term, and then die yourself. Which do you choose?

Now this: You are a husband with children. You come home from work and find a man in your home, threatening your wife and children with a gun. You can attack the man and risk your life, or you can give in to all his demands and potentially endanger your family. Which would you do?

Finally, this one: you are walking down the street, going home after a long Monday at work and a single watery beer with your friends. You pass an alley and hear what sounds like a scuffle. You peek around the corner of the building and see two very muscular men in a fist fight. As soon as you blink, one of the men falls to the ground as the other stands over him and pulls a switchblade from his pocket. You don’t know if you’re about to witness a murder or just a lesson in street life involving scars, but the man on the ground is terrified. You don’t have time to call the police or even attract enough attention from other passerby to back you up. All you have time for is a decision between walking away and making your presence known. If the man with the knife realizes you’re there, he could run away, attack the fallen man anyway, or throw the knife at you. You have three seconds to decide. What do you choose?

These are situations no one wants to be in—having to decide whether to die to save another person’s life. No matter the choice, someone will live, and someone will die. Possibly you. Unfortunately, the time for deciding is usually limited to a few seconds. We all know what we would like our choice to be, but no one is sure they would really do it. And there is no law, whether institutional or natural, to guide our decision. In John 15:13 we have the famous passage, “No one has greater love than this, to lay down one’s life for one’s friends.” Yet the Catechism of the Catholic Church also says that there is a “natural inclination of the human being to preserve and perpetuate his life,” and that “[l]ove towards oneself remains a fundamental principle of morality,” which is why suicide is wrong.

Watching another person die is terrible, but doing anything that would cause our own death is even harder. Our repulsion from self-destruction is based partly on the fear of the unknown but even more so on our instinct to survive. Making conscious decisions that will end in our death goes against everything in us. It contradicts the hardwiring of the body and the desire of the mind. People are capable of surviving horrific conditions for incredible lengths of time—the concentration camps of World War II and the gulags of the Soviet Union are proof of that—which would not be possible if we had not been made with the physical ability and the mental desire to survive. Dying for any reason, even to save the life of another person, means that we are going directly against our ourselves.

Yet our desire to live is another reason to die. Just as we do not want to die, so no one else does either. And we know that. This is why we hate murder. Death goes so completely against human instinct that we do not want anyone to experience it, especially if we have the power to stop it. We go to great lengths, doing whatever we can, to help people avoid death. Scientists perform risky experiments, doctors perform surgeries for hours on end, and families spend fortunes on medical care. In the case of families, the willingness to sacrifice is understandable—they do not want to lose someone they love. But in the case of doctors, the willingness is less obvious. They put themselves through great physical and mental strain to save the life of someone they may never have met. They see the suffering and the flirting with death, but there is no personal connection. Yet they spend their lives stooped over surgical tables, bloodying their hands to save people. Scientists’ reasons are even less explicit. They do not even see the people their work saves. They do not touch them, they do not hear them. They do not meet the scared families. Yet they spend their lives in laboratories, pouring over microscopes and calculations to save people. This is not to say that the sacrifice of a doctor or a family is any less than that of a scientist, but to point out that everyone, even complete strangers, does what they can to save the lives of other people.

But dying to save another is an extreme act of sacrifice. It is so extreme that we call it “the ultimate sacrifice.” There is nothing more demanding, more completely selfless, than this. We are in awe of those who give that much, but the stories also scare us because it makes us realize that we may be faced with a similar decision. When we hear stories of soldiers sacrificing themselves for each other we hail them as heroes, but we do not criticize those who instead choose to live themselves. We admire saints like Maximilian Kolbe and Gianna Molla who died to give their friends or children life, but we do not condemn those who do not do likewise. The Church even says that it is acceptable for a terminally ill pregnant woman to have treatment or procedures done that would save her life but indirectly cause the death of the child.

Thus we are left with social and moral support for both choices—allow the other person to die, or allow ourselves to die. Yet despite the wrenching decision, we have the comfort of knowing that whatever we choose, it will be right, and we will be saving a life. In the meantime, we can all pray that we are never forced to make a decision either way.

As someone with younger sisters, I like to think that I would risk a life-threatening surgery to save either of their lives. As a young woman who hopes to have a family someday, I’m terrified at the thought of leaving my children without a mother, but I hope I would choose my baby’s life over my own if I developed cancer while pregnant. As someone who hopes to have a strong, protective husband for myself and my children, but also as someone who would (presumably, hopefully) rather be hurt myself than see any of them get hurt, I really don’t know what I would want my husband to do if my children and I were being threatened. And as a young woman who could probably be broken in half by the vast majority of men in the world, but also as one who does not like to see people get beat up, I would probably step out into the alley from around the building, say something in a very small voice, and hope that either an ex-military police officer or my guardian angel saved me. But hopefully I’m never faced with any of these situations.