The lecture begins with a simple question that does not stay simple for long.

What should you do if a runaway trolley is heading toward five workers on the track, and you can turn it onto another track where it will kill one instead?

At first, the problem feels mechanical. Clean. Almost mathematical. One life against five. Many people answer quickly: turn the trolley. Better to kill one than let five die. The reasoning seems straightforward because it focuses on outcomes. If morality is about reducing harm and saving the greatest number of lives, then sacrificing one to save five appears not only permissible, but right.

This is the first doorway into consequentialism.

Consequentialist thinking asks us to judge actions by their results. If one choice leads to more overall well-being, fewer deaths, or greater benefit, then that choice seems morally preferable. In this first trolley case, many people discover that their instinct leans naturally in that direction. They accept the burden of choosing the lesser loss.

But then the lecture changes one detail.

Now you are no longer the driver of the trolley. You are standing on a bridge above the tracks. Below you, the trolley is still racing toward five workers. Beside you stands a very large man. If you push him off the bridge, his body will stop the trolley, and the five workers will live. He will die.

Suddenly, the arithmetic is the same, but the moral feeling is completely different.

Most people who would switch the trolley refuse to push the man.

That contrast is the heart of the lecture’s opening challenge. Why does it feel acceptable to redirect a trolley toward one person but not to directly use one person’s body as the instrument of rescue? The outcomes are structurally similar: one dies, five survive. Yet our intuitions diverge sharply.

That is where the second major moral framework appears: categorical moral reasoning.

This view holds that some actions are wrong in themselves, regardless of their consequences. On this way of thinking, intentionally killing an innocent person, or using a person merely as a means to an end, violates a moral duty that numbers alone cannot erase. The lecture invites students into that tension immediately. It does not resolve the issue. It sharpens it.

The same pattern deepens through medical examples.

Suppose a doctor in an emergency room can save five moderately injured patients or spend all available resources trying to save one severely injured patient. Many people again choose the five. But then the scenario changes. A healthy patient walks in for a checkup. Five dying patients each need organ transplants. Should the doctor kill the healthy patient and distribute the organs to save the five?

Almost everyone recoils.

Once again, pure outcome-based reasoning seems to collide with something deeper—something about rights, innocence, and the moral limits of calculation.

By this point, the lecture has already done something powerful: it shows that our moral instincts are not as consistent as we might assume. We often think we know what justice requires, but when scenarios shift slightly, our certainty cracks. We save five in one case, refuse to sacrifice one in another, and struggle to explain exactly why.

That discomfort is not a flaw in the lecture.

It is the point.

Because the study of justice begins not when we have easy answers, but when we realize our strongest convictions may rest on principles we have never fully examined.

Part 2

After the hypothetical dilemmas, the lecture turns to a real case—one far more disturbing because it actually happened.

The case is The Queen v. Dudley and Stephens.

Four sailors are stranded after a shipwreck. Days pass. Then more days. They have almost no food, almost no water, and no realistic hope of rescue. With starvation closing in, two of the men—Dudley and Stephens—kill the cabin boy, Richard Parker, and eat him in order to survive.

The facts are brutal, but the moral question is even more brutal.

Was it murder?
Or was it necessity?

Here, the classroom’s debate becomes more intense, because the trolley problem is no longer abstract. There are no switches, no tracks, no simplified variables. There are human beings trapped between death and desperation. Some students defend the sailors by appealing to survival. If everyone would otherwise die, then sacrificing one to save three may seem, from a purely consequentialist standpoint, tragically justified.

But others reject that reasoning completely.

They argue that murder remains murder, even in extremity. That necessity may explain an act, but not morally cleanse it. That some lines cannot be crossed without destroying the very moral structure that makes survival meaningful at all.

The lecture then introduces another layer: consent.

Would the case be different if the sailors had drawn lots fairly? If everyone had agreed in advance to a lottery, and the cabin boy had lost, would that make the killing just? Or merely procedural? Some argue that consent matters deeply because it transforms coercion into agreement. Others argue that under such extreme conditions, “consent” may be compromised by desperation. Still others insist that no consent can authorize murder.

This is where the lecture becomes especially rich.

It is no longer only asking whether consequences justify actions. It is also asking what role fairness, procedure, and consent play in moral judgment. A lottery feels fairer than arbitrary selection, but does fairness in method make the act itself morally acceptable? If someone agrees to die to save others, do we honor that choice, or do we still prohibit the killing because human life should never be treated as a resource?

The case exposes how unstable moral certainty can become under real pressure.

It also shows why justice cannot be reduced to instinct alone. Our instincts may tell us one thing in a trolley problem, another in a lifeboat, and still another when the case is filtered through law. The legal system convicted Dudley and Stephens of murder, rejecting necessity as a defense. That decision reflects more than punishment. It reflects a judgment about the kind of society law is meant to protect.

A society that permits killing whenever outcomes seem favorable may preserve lives in some cases, but it may also lose something essential—namely, the principle that persons possess a dignity beyond usefulness.

And that brings the lecture to its deeper question:

Why do we believe that some acts are simply wrong, even when they seem to maximize survival or happiness?

That question opens the door to two of the philosophers the course will study most carefully:

• Jeremy Bentham, who argues from utility and the maximization of happiness.

• Immanuel Kant, who insists that moral duties are not negotiable and that people must never be treated merely as means.

The students are not yet asked to choose definitively between them.

They are asked to feel the force of both.

Part 3

By the end of the lecture, justice no longer looks like a set of obvious rules.

It looks like a field of conflict—between intuitions, between principles, between outcomes and duties, between sympathy and law, between what feels merciful and what feels inviolable. That is exactly why the course begins this way. Not with definitions, but with dilemmas. Not with certainty, but with disturbance.

The lecture makes clear that philosophy is risky.

It is risky because once you begin asking these questions seriously, familiar beliefs stop feeling automatic. Why is killing one to save five acceptable in one case but not another? Why do directness, intention, and proximity matter so much? Why do fairness and consent seem morally relevant in some situations but insufficient in others? Why do we sometimes think justice requires maximizing welfare, and at other times believe justice must protect rights even at terrible cost?

These are not merely classroom puzzles.

They reach into law, politics, medicine, war, free speech, equality, military conscription, and everyday moral life. The lecture warns students that philosophy can unsettle political loyalties and personal convictions because it forces them to give reasons for beliefs they may have inherited without examination.

It also addresses skepticism.

Some people respond to these tensions by saying that moral philosophy only proves how confusing everything is—that there are no real answers, only endless arguments. But the lecture rejects that as a final refuge. We cannot escape moral reasoning, because life constantly demands judgments from us. We choose policies. We assign blame. We distribute burdens. We decide what can be traded off and what cannot. Even refusing to answer is itself a kind of answer.

So the task is not to avoid moral conflict.

It is to think through it more honestly.

That is why the course turns next toward the great traditions of moral and political philosophy:

• Bentham and Mill, asking whether justice can be grounded in utility and aggregate happiness.

• Kant, arguing that morality depends on duty, dignity, and principles that cannot be sacrificed for convenience.

• Later, thinkers like Aristotle and Locke, who explore virtue, rights, citizenship, and the purposes of political life.

What the opening lecture establishes is the enduring tension between two visions of justice:

One says justice is about producing the best consequences.
The other says justice is about respecting certain moral limits, no matter the cost.

Neither side is easy.
Neither side leaves our intuitions untouched.

And that is exactly why the course matters.

Because justice is not just a legal topic or a philosophical abstraction. It is the question beneath every public argument and every private dilemma: What do we owe one another, and why?

The lecture ends by inviting students into that uncomfortable but necessary work. Not to memorize doctrines, but to test them. Not to cling to intuition blindly, but to examine it. Not to seek easy moral comfort, but to become capable of reasoned judgment.

That is what makes the opening so powerful.

A trolley, a bridge, a surgeon, a lifeboat, and a murdered cabin boy—each case strips away moral complacency. Each forces the same unsettling realization: justice is not only about what happens. It is also about what we are willing to do, what we refuse to do, and what kind of human beings we become when forced to choose.