Ethical theories explained: a beginner’s guide to how philosophers judge right and wrong

Every year I ask my Grade 12 students the same question on the first day of our ethics unit. Your best friend cheated on the final exam and is about to receive the class award that should have gone to someone else, a quiet student who studied for months. Do you tell the teacher?

Within five minutes the room has divided, and what fascinates me is not the split but the reasons. One student says, "Think of what happens to the friendship." Another says, "Cheating is wrong, period." A third asks, "What would a good person do?" A fourth says, "What about the girl who actually earned it?" Without knowing it, they have just reinvented the main families of ethical theory. This guide is for anyone who wants names for what those students were doing.

The key idea is simple. Each ethical theory tells you where to look when you are deciding whether an act is right.

Look at the consequences

Consequentialism says an act is right if it produces the best outcome. Its best-known form, utilitarianism, was developed by Jeremy Bentham and John Stuart Mill: the right act is the one that produces the greatest happiness for everyone affected, with each person's happiness counting equally. Long before them, the Chinese philosopher Mozi argued that practices should be judged by whether they actually benefit people, counting everyone impartially.

For my exam case, the consequentialist adds up the effects: harm to the friend, fairness to the deserving student, the effect on everyone's trust in grades. The theory's strength is its clarity. Its weakness shows when the arithmetic recommends something terrible, like punishing an innocent person to calm an angry crowd.

Look at the act itself

Duty-based, or deontological, ethics says some acts are right or wrong in themselves, whatever their consequences. Immanuel Kant's central test asks whether you could will the principle behind your action to become a universal law. A policy of lying whenever it helps a friend could not work if everyone followed it, because no one would believe anyone. Kant also insisted that we must treat people always as ends in themselves, never merely as means. The strength: it explains why some things are simply off-limits. The weakness: rules can collide, and sometimes consequences really do seem to matter.

Look at the person

Virtue ethics, going back to Aristotle, asks not "what rule applies?" but "what would a person of good character do?" Virtues like courage, honesty and justice are stable traits built through practice, and each lies between two extremes: courage, for example, sits between cowardice and recklessness. The skill of seeing what a particular situation requires Aristotle called practical wisdom. My students like this one because it sounds like real life. Its weakness is that "do what a virtuous person would do" is hard to apply when you are not sure what that is.

Look at what everyone could agree to

Contract-based theories, from Hobbes to John Rawls and T. M. Scanlon, say that right action follows rules people could agree to under fair conditions. Rawls asked us to imagine choosing principles behind a "veil of ignorance", not knowing which position in society we would end up in. Would you accept a rule letting cheaters keep their awards if you did not know whether you would be the cheater or the student who lost out?

Look at the relationship

The ethics of care, developed by Carol Gilligan, Nel Noddings and Virginia Held, starts from the fact that all of us depend on others, as infants, when sick, when old. It says moral attention begins with particular relationships and responsibilities, not with abstract principles applied to strangers. For my students, care ethics takes the friendship seriously without letting it decide everything, because the deserving student is also someone, with people who care about her.

Look at the role

Confucian ethics, on one influential reading, asks what this relationship requires of someone standing where you stand: as child, parent, student, friend or official. Its key notions are ren, often translated "benevolence" though it means something closer to full humanity, and li, ritual propriety, the practised forms that shape character. Here the answer depends partly on who you are: the class president, an ordinary classmate, or the friend's cousin.

Look at the community

Ubuntu, from southern Africa, is often summed up in the Nguni saying umuntu ngumuntu ngabantu: a person is a person through other persons. On this view an act is right when it builds and sustains the shared life through which we become persons at all. Desmond Tutu made the idea known around the world. An ubuntu response to my case would look for a way to restore relationships, including the friend's place in the class, rather than one that simply punishes or simply protects.

Look at what has been commanded

Divine command theories hold that moral obligation depends on God's command. They are serious philosophical positions with long debates behind them in Christian, Jewish and Islamic thought, especially over whether things are good because God commands them or commanded because they are good.

What I want beginners to take away

Many introductions present these theories like a menu: pick one and defend it to the death. I think that is a mistake, for three reasons.

First, the theories agree far more often than their arguments suggest. In my exam case, the duty theorist, the virtue theorist and the contract theorist all say "tell the truth", for completely different reasons. Disagreement shows up mainly in hard cases, and there it usually concerns whose interests count and how much.

Second, each theory is best understood as noticing something the others underplay. Consequences matter. Some acts are wrong whatever they achieve. Character is formed by what we repeatedly do. Fairness is what we could justify to each other. Relationships are not optional extras. That is why most thoughtful people use several lenses, even if they rank them differently.

Third, be careful with quick translations between traditions. My students often recognise in care ethics and ubuntu something like our Filipino idea of kapwa, which the psychologist Virgilio Enriquez described as a shared self, the sense that the other person is not simply "other". That recognition is real and useful. But kapwa, ren and ubuntu each come from a particular way of life, and treating them as three words for one thing loses what each has to teach.

If you want to begin, read a short dialogue of Plato, Mill's Utilitarianism, Kant's Groundwork of the Metaphysics of Morals, a few books of the Analects, and something by Nel Noddings. Then come back to my exam case and see whether your answer has changed. My students' answers usually don't. Their reasons always do.