This excerpt is from Michael J. Sandel,

Justice: What's the Right Thing to Do?, 

pp. 21-30, by permission of the publisher.

The Runaway Trolley

Suppose you are the driver of a trolley car hurtling down the track at sixty miles an hour. Up ahead you see five workers standing on the track, tools in hand. You try to stop, but you can’t. The brakes don’t work. You feel desperate, because you know that if you crash into these five workers, they will all die. (Let’s assume you know that for sure.)

Suddenly, you notice a side track, off to the right. There is a worker on that track, too, but only one. You realize that you can turn the trolley car onto the side track, killi ng the one worker, but sparing the five.

What should you do? Most people would say, “Turn! Tragic though it is to kill one innocent person, it’s even worse to kill five.” Sacrificing one life in order to save five does seem the right thing to do.

Now consider another version of the trolley story. This time, you are not the driver but an onlooker, standing on a bridge overlooking the track. (This time, there is no side track.) Down the track comes a trolley, and at the end of the track are five workers. Once again, the brakes don’t work. The trolley is about to crash into the five workers. You feel helpless to avert this disaster—until you notice, standing next to you on the bridge, a very heavy man. You could push him off the bridge, onto the track, into the path of the oncoming trolley. He would die, but the five workers would be saved. (You consider jumping onto the track yourself, but realize you are too small to stop the trolley.)

Would pushing the heavy man onto the track be the right thing to do? Most people would say, “Of course not. It would be terribly wrong to push the man onto the track.”

Pushing someone off a bridge to a certain death does seem an awful thing to do, even if it saves five innocent lives. But this raises a moral puzzle: Why does the principle that seems right in the first case—sacrifice one life to save five—seem wrong in the second?

If, as our reaction to the first case suggests, numbers count—if it is better to save five lives than one—then why shouldn’t we apply this principle in the second case, and push? It does seem cruel to push a man to his death, even for a good cause. But is it any less cruel to kill a man by crashing into him with a trolley car?

Perhaps the reason it is wrong to push is that doing so uses the man on the bridge against his will. He didn’t choose to be involved, after all. He was just standing there.

But the same could be said of the person working on the side track. He didn’t choose to be involved, either. He was just doing his job, not volunteering to sacrifice his life in the event of a runaway trolley. It might be argued that railway workers willingly incur a risk that bystanders do not. But let’s assume that being willing to die in an emergency to save other people’s lives is not part of the job description, and that the worker has no more consented to give his life than the bystander on the bridge has consented to give his.

Maybe the moral diff erence lies not in the eff ect on the victims— both wind up dead—but in the intention of the person making the decision. As the driver of the trolley, you might defend your choice to divert the trolley by pointing out that you didn’t intend the death of the worker on the side track, foreseeable though it was; your purpose would still have been achieved if, by a great stroke of luck, the five workers were spared and the sixth also managed to survive.

But the same is true in the pushing case. The death of the man you push off the bridge is not essential to your purpose. All he needs to do is block the trolley; if he can do so and somehow survive, you would be delighted.

Or perhaps, on reflection, the two cases should be governed by the same principle. Both involve a deliberate choice to take the life of one innocent person in order to prevent an even greater loss of life. Perhaps your reluctance to push the man off the bridge is mere squeamishness, a hesitation you should overcome. Pushing a man to his death with your bare hands does seem more cruel than turning the steering wheel of a trolley. But doing the right thing is not always easy.

We can test this idea by altering the story slightly. Suppose you, as the onlooker, c ould cause the large man standing next to you to fall onto the track without pushing him; imagine he is standing on a trap door that you could open by turning a steering wheel. No pushing, same result. Would that make it the right thing to do? Or is it still morally worse than for you, as the trolley d river, to turn onto the side track?

It is not easy to explain the moral diff erence between these cases— why turning the trolley seems right, but pushing the man off the bridge seems wrong. But notice the pressure we feel to reason our way to a convincing distinction between them—and if we cannot, to reconsider our judgment about the right thing to do in each case. We sometimes think of moral reasoning as a way of persuading other people. But it is also a way of sorting out our own moral convictions, of figuring out what we believe and why.

Some moral dilemmas arise from conflicting moral principles. For example, one principle that comes into play in the trolley story says we should save as many lives as possible, but another says it is wrong to kill an innocent person, even for a good cause. Confronted with a situation in which saving a number of lives depends on killing an innocent person, we face a moral quandary. We must try to figure out which principle has greater weight, or is more appropriate under the circumstances.

Other moral dilemmas arise because we are uncertain how events will unfold. Hypothetical examples such as the trolley story remove the uncertainty that hangs over the choices we confront in real life. They assume we know for sure how many will die if we don’t turn— or don’t push. This makes such stories imperfect guides to action. But it also makes them useful devices for moral analysis. By setting aside contingencies—“What if the workers noticed the trolley and jumped aside in time?”—hypothetical examples help us to isolate the moral principles at stake and examine their force.

The Afghan Goatherds

Consider now an actual moral dilemma, similar in some ways to the fanciful tale of the runaway trolley, but complicated by uncertainty about how things will turn out:

In June 2005, a special forces team made up of Petty Officer Marcus Luttrell and three other U.S. Navy SEALs set out on a secret reconnaissance mission in Afghanistan, near the Pakistan border, in search of a Taliban leader, a close associate of Osama bin Laden.37 According to intelligence reports, their target commanded 140 to 150 heavily armed fighters and was staying in a village in the forbidding mountainous region.

Shortly after the special forces team took up a position on a mountain ridge overlooking the village, two Afghan farmers with about a hundred bleating goats happened upon them. With them was a boy about fourteen years old. The Afghans were unarmed. The American soldiers trained their rifles on them, motioned for them to sit on the ground, and then debated what to do about them. On the one hand, the goatherds appeared to be unarmed civilians. On the other hand, letting them go would run the risk that they would inform the Taliban of the presence of the U.S. soldiers.

As the four soldiers contemplated their options, they realized that they didn’t have any rope, so tying up the Afghans to allow time to find a new hideout was not feasible. The only choice was to kill them or let them go free.

One of Luttrell’s comrades argued for killing the goatherds: “We’re on active duty behind enemy lines, sent here by our se nior commanders. We have a right to do every thing we can to save our own lives. The military decision is obvious. To turn them loose would be wrong.”38 Luttrell was torn. “In my soul, I knew he was right,” he wrote in retrospect. “We could not possibly turn them loose. But my trouble is, I have another soul. My Chris tian soul. And it was crowding in on me. Something kept whispering in the back of my mind, it would be wrong to execute these unarmed men in cold blood.”39 Luttrell didn’t say what he meant by his Chris tian soul, but in the end, his conscience didn’t allow him to kill the goatherds. He cast the deciding vote to release them. (One of his three comrades had abstained.) It was a vote he came to regret.

About an hour and a half after they released the goatherds, the four soldiers found themselves surrounded by eighty to a hundred Taliban fighters armed with AK-47s and rocket-propelled grenades. In the fierce firefight that followed, all three of Luttrell’s comrades were killed. The Taliban fighters also shot down a U.S. helicopter that sought to rescue the SEAL unit, killing all sixteen soldiers on board.

Luttrell, severely injured, managed to survive by falling down the mountainside and crawling seven miles to a Pashtun village, whose residents protected him from the Taliban until he was rescued.

In retrospect, Luttrell condemned his own vote not to kill the goatherds. “It was the stupidest, most southern-fried, lamebrained decision I ever made in my life,” he wrote in a book about the experience. “I must have been out of my mind. I had actually cast a vote which I knew could sign our death warrant. . . . At least, that’s how I look back on those moments now. . . . The deciding vote was mine, and it will haunt me till they rest me in an East Texas grave.”40

Part of what made the soldiers’ dilemma so difficult was uncertainty about what would happen if they released the Afghans. Would they simply go on their way, or would they alert the Taliban? But suppose Luttrell knew that freeing the goatherds would lead to a devastating battle resulting in the loss of his comrades, nineteen American deaths, injury to himself, and the failure of his mission? Would he have decided diff erently?

For Luttrell, looking back, the answer is clear: he should have killed the goatherds. Given the disaster that followed, it is hard to disagree. From the standpoint of numbers, Luttrell’s choice is similar to the trolley case. Killing the three Afghans would have saved the lives of his three comrades and the sixteen U.S. troops who tried to rescue them. But which version of the trolley story does it resemble? Would killing the goatherds be more like turning the trolley or pushing the man off the bridge? The fact that Luttrell anticipated the danger and still c ould not bring himself to kill unarmed civilians in cold blood suggests it may be closer to the pushing case.

And yet the case for killing the goatherds seems somehow stronger than the case for pushing the man off the bridge. This may be because we suspect that—given the outcome—they were not innocent bystanders, but Taliban sympathizers. Consider an analogy: If we had reason to believe that the man on the bridge was responsible for disabling the brakes of the trolley in hopes of killing the workers on the track (let’s say they were his enemies), the moral argument for pushing him onto the track would begin to look stronger. We would still need to know who his enemies were, and why he wanted to kill them. If we learned that the workers on the track were members of the French resis tance and the heavy man on the bridge a Nazi who had sought to kill them by disabling the trolley, the case for pushing him to save them would become morally compelling.

It is possible, of course, that the Afghan goatherds were not Taliban sympathizers, but neutrals in the conflict, or even Taliban opponents, who were forced by the Taliban to reveal the presence of the American troops. Suppose Luttrell and his comrades knew for certain that the goatherds meant them no harm, but would be tortured by the Taliban to reveal their location. The Americans might have killed the goatherds to protect their mission and themselves. But the decision to do so would have been more wrenching (and morally more questionable) than if they knew the goatherds to be pro-Taliban spies.

Moral Dilemmas

Few of us face choices as fateful as those that confronted the soldiers on the mountain or the witness to the runaway trolley. But wrestling with their dilemmas sheds light on the way moral argument can proceed, in our personal lives and in the public square.

Life in dem o cratic societies is rife with disagreement about right and wrong, justice and injustice. Some p eople favor abortion rights, and others consider abortion to be murder. Some believe fairness requires taxing the rich to help the poor, while others believe it is unfair to tax away money people have earned through their own eff orts. Some defend affirmative action in college admissions as a way of righting past wrongs, whereas others consider it an unfair form of reverse discrimination against people who deserve admission on their merits. Some people reject the torture of terror suspects as a moral abomination unworthy of a free society, while others defend it as a last resort to prevent a terrorist attack.

Elections are won and lost on these disagreements. The so-called culture wars are fought over them. Given the passion and intensity with which we debate moral questions in public life, we might be tempted to think that our moral convictions are fixed once and for all, by upbringing or faith, beyond the reach of reason.

But if this were true, moral persuasion would be inconceivable, and what we take to be public debate about justice and rights would be nothing more than a volley of dogmatic assertions, an ideological food fight.

At its worst, our politics comes close to this condition. But it need not be this way. Sometimes, an argument can change our minds.

How, then, can we reason our way through the contested terrain of justice and injustice, equality and inequality, individual rights and the common good? This book tries to answer that question.

One way to begin is to notice how moral reflection emerges naturally from an encounter with a hard moral question. We start with an opinion, or a conviction, about the right thing to do: “Turn the trolley onto the side track.” Then we reflect on the reason for our conviction, and seek out the principle on which it is based: “Better to sacrifice one life to avoid the death of many.” Then, confronted with a situation that confounds the principle, we are pitched into confusion: “I thought it was always right to save as many lives as possible, and yet it seems wrong to push the man off the bridge (or to kill the unarmed goatherds).” Feeling the force of that confusion, and the pressure to sort it out, is the impulse to philosophy.

Confronted with this tension, we may revise our judgment about the right thing to do, or rethink the principle we initially espoused. As we encounter new situations, we move back and forth between our judgments and our principles, revising each in light of the other. This turning of mind, from the world of action to the realm of reasons and back again, is what moral reflection consists in.

This way of conceiving moral argument, as a dialectic between our judgments about particular situations and the principles we affirm on reflection, has a long tradition. It goes back to the dialogues of Socrates and the moral philosophy of Aristotle. But notwithstanding its ancient lineage, it is open to the following challenge:

If moral reflection consists in seeking a fit between the judgments we make and the principles we affirm, how can such reflection lead us to justice, or moral truth? Even if we succeed, over a lifetime, in bringing our moral intuitions and principled commitments into alignment, what confidence can we have that the result is anything more than a self-consistent skein of prejudice?

The answer is that moral reflection is not a solitary pursuit but a public endeavor. It requires an interlocutor—a friend, a neighbor, a comrade, a fellow citizen. Sometimes the interlocutor can be imagined rather than real, as when we argue with ourselves. But we cannot discover the meaning of justice or the best way to live through introspection alone.

In Plato’s Republic, Socrates compares ordinary citizens to a group of prisoners confined in a cave. All they ever see is the play of shadows on the wall, a reflection of objects they can never apprehend. Only the philosopher, in this account, is able to ascend from the cave to the bright light of day, where he sees things as they really are. Socrates suggests that, having glimpsed the sun, only the philosopher is fit to rule the cave dwellers, if he can somehow be coaxed back into the darkness where they live.

Plato’s point is that to grasp the meaning of justice and the nature of the good life, we must rise above the prejudices and routines of everyday life. He is right, I think, but only in part. The claims of the cave must be given their due. If moral reflection is dialectical—if it moves back and forth between the judgments we make in concrete situations and the principles that inform those judgments—it needs opinions and convictions, however partial and untutored, as ground and grist. A philosophy untouched by the shadows on the wall can only yield a sterile utopia.

When moral reflection turns political, when it asks what laws should govern our collective life, it needs some engagement with the tumult of the city, with the arguments and incidents that roil the public mind. Debates over bailouts and price gouging, income inequality and affirmative action, military ser vice and same-sex marriage, are the stuff of political philosophy. They prompt us to articulate and justify our moral and political convictions, not only among family and friends but also in the demanding company of our fellow citizens.

More demanding still is the company of political philosophers, ancient and modern, who thought through, in sometimes radical and surprising ways, the ideas that animate civic life—justice and rights, obligation and consent, honor and virtue, morality and law. Aristotle, Immanuel Kant, John Stuart Mill, and John Rawls all figure in these pages. But their order of appearance is not chronological. This book is not a history of ideas, but a journey in moral and political reflection. Its goal is not to show who influenced whom in the history of political thought, but to invite readers to subject their own views about justice to critical examination—to figure out what they think, and why.