What Is Ethics? Branches, Theories and the Questions Philosophers Ask

Ethics, or moral philosophy, is the branch of philosophy that asks how we ought to live: what makes an action right or wrong, what kind of person is worth becoming, and what is good for a human life. It has three levels: what moral claims are (meta-ethics), which acts are right (normative ethics) and hard cases (applied ethics).

On The Coordinates, ethics is Root III, Ethics and Axiology: 21 question cards that run from “When you say cruelty is wrong, what kind of statement are you making?” to “Does a forest matter only because people value it?” Each card sets out the rival answers side by side and names who gave them, from Mencius and Miskawayh to Kant and Carol Gilligan. Two cards carry the contested mark (△), because philosophers disagree about how the question itself should be framed.

What is ethics in philosophy?

The word comes from the Greek ēthos, meaning character or custom; “morality” comes from the Latin mores, customs. Both point at the same territory: the standards by which we judge conduct, character and whole lives. Ethics as a branch of philosophy examines those standards rather than simply following them. It asks what justifies them, where they conflict, and whether they hold for everyone.

No experiment settles whether lying to protect a friend is permissible. Two people can agree on every fact about the situation and still disagree, because the disagreement is about what those facts mean for what should be done.

Ethics vs morality: is there a difference?

In everyday English the two words are often interchangeable. When a distinction is drawn, “morality” usually means the actual beliefs and practices a person or community lives by, while “ethics” means systematic reflection on them, or, in professional settings, a written code such as a medical or business code of conduct.

Some philosophers draw the line more sharply. Hegel contrasted individual conscience (Moralität) with the ethical life embodied in a community’s customs and institutions (Sittlichkeit). Bernard Williams treated “morality” as one narrow system within ethics, built around obligation and blame, and held that ethics is the wider question of how one should live. The distinction is a reminder that ethics covers more than rules about what is forbidden.

The branches of ethics

Most introductions divide ethics into three branches, and the cards follow the same order, adding two neighbouring fields:

• Meta-ethics asks what a moral claim is: whether “wrong” names a fact, expresses a feeling, or does something else.
• Normative ethics asks what makes acts right or wrong. This is where the ethical theories live.
• Applied ethics works on actual cases in medicine, the environment, business, technology, war and our treatment of animals.
• Moral psychology asks what in human beings makes moral life possible.
• Value theory, or axiology, asks what is worth having or pursuing at all, a wider question than morality.

The levels depend on one another: applied ethics draws on normative theories and tests them against hard cases. Here is every card in the root, each linked to its rival answers. The 131 cards across all six roots come from The Coordinates of Thought by Syed Raheel Shahzad.

Meta-ethics: what is a moral claim?

The Meta-Ethics card begins with a deceptively simple question: when you say cruelty is wrong, what kind of statement are you making? Realists answer that you are reporting a fact. Some, following G. E. Moore, hold that moral facts are non-natural and cannot be reduced to anything else; others hold that they are natural facts about welfare or human function.

Anti-realists deny that there are mind-independent moral facts. Emotivists such as A. J. Ayer read “cruelty is wrong” as an expression of feeling, and R. M. Hare read moral claims as universalisable prescriptions. J. L. Mackie’s error theory holds that moral claims do aim to report facts, but that no such facts exist, so positive moral claims are all false. Relativists make moral truth relative to a framework; constructivists hold that it is what an idealised rational procedure would yield.

The test case on Moral Realism vs Anti-Realism is stark: if everyone approved of torturing children, would it still be wrong? The debate is old and not only European. Plato’s Euthyphro asks whether the pious is loved by the gods because it is pious, or pious because they love it. In Islamic theology the Mu’tazila held that right and wrong can be known by reason, while al-Ash’ari and his followers grounded obligation in the divine command. David Hume observed that arguments often slide from what is to what ought to be without explaining the step, a gap meta-ethics still argues over. Further cards ask how moral knowledge would work (Moral Epistemology) and whether you can know an act is wrong and be entirely unmoved (Moral Motivation).

Normative ethics: the main ethical theories

Normative Ethics asks what you should look at to tell whether an act is right. Each of the major ethical theories gives a different answer.

Approach	What it looks at	Classic figures
Consequence-based (consequentialism, utilitarianism)	The outcome: did the act produce the best results?	Mozi, Jeremy Bentham, J. S. Mill, Henry Sidgwick, Peter Singer
Duty-based (deontology)	The act itself: does it follow a principle you could universalise, or respect rights?	Immanuel Kant, Thomas Aquinas, W. D. Ross, Christine Korsgaard
Character-based (virtue ethics)	The agent: is it what a person of good character would do?	Aristotle, Confucius, Mencius, Miskawayh, Elizabeth Anscombe, Iris Murdoch
Contract-based (contractualism)	Agreement: would the parties affected accept a rule permitting it?	Thomas Hobbes, Jean-Jacques Rousseau, John Rawls, T. M. Scanlon
Care-based (ethics of care)	The relationship: does it respond well to those who depend on you?	Carol Gilligan, Nel Noddings, Eva Kittay, Virginia Held
Divine command	The command: does it accord with what God has commanded?	Al-Ash’ari, William of Ockham, Robert Adams

Consequentialists face the question on their card: if an act produces the best outcome, can it be wrong? Deontologists answer that some things are wrong even when they would do good, such as punishing an innocent person to calm a mob. Virtue ethicists move the question from what to do to who to be, and contractualists ask whether you could justify your act to everyone it affects. Care ethicists argue that impartial principles leave out the particular people we are responsible for.

The card also lists approaches that do not fit neatly into these six. Confucian role ethics holds that rightness is what a relationship, such as parent and child or friend and friend, requires of someone in your position. Ubuntu, associated in recent decades with Desmond Tutu, locates moral life in personhood held in common: a person becomes a person through other persons. Ross’s pluralism holds that we have several duties at once, to be weighed by judgement without a master rule.

Applied ethics: from theory to cases

Applied Ethics asks the most practical question in philosophy: what should be done in this case? Its six cards cover the domains where moral questions arise often enough, and with enough at stake, to have built their own literatures:

• Bioethics and Medical Ethics △: who counts, who decides, and who gets it? Modern medical ethics often works with four principles set out by Beauchamp and Childress: autonomy, beneficence, non-maleficence and justice.
• Environmental Ethics: does a forest matter only because people value it? Positions run from anthropocentrism through sentientism and biocentrism to ecocentrism, stewardship and deep ecology.
• Business and Economic Ethics: does a company owe anything to anyone but its owners? Milton Friedman’s shareholder view stands against stakeholder theory, Islamic commercial ethics and Catholic social teaching.
• Ethics of Technology and AI: who is responsible when a machine causes harm and no one intended it? Issues include responsibility gaps, value alignment, bias inherited from data and concentrated power.
• War and Political Violence △: can killing be permitted when it would otherwise be murder? Pacifism, just war theory (from Augustine and Aquinas to Michael Walzer) and political realism give different answers.
• Animal Ethics: what is it about humans that makes us count? The Jain teacher Mahavira taught non-harm towards all living beings; Bentham, Peter Singer and Tom Regan ask whether the capacity to suffer, or being the subject of a life, gives animals moral standing.

Across these domains the same structural questions recur: which beings count and how much, whether allowing harm differs from doing it, whether foreseen harm differs from intended harm (the doctrine of double effect, usually traced to Aquinas), and who gets what under scarcity. The trolley problem, introduced by Philippa Foot and developed by Judith Jarvis Thomson, is a thought experiment built to isolate exactly these differences.

Moral psychology and value theory (axiology)

Moral Psychology asks whether people are naturally good, naturally selfish, or naturally neither. In ancient China, Mencius held that human beings are born with sprouts of goodness that need cultivation; Xunzi replied that human nature inclines to selfishness and must be reshaped by ritual and learning. Hume and Adam Smith grounded morality in sentiment and sympathy, rationalists in reason, and psychologists such as Jonathan Haidt study how fast intuition and slow deliberation interact.

Value Theory, also called axiology (from the Greek axios, worthy), asks something wider than morality: what would make your life go well, apart from being moral? The main answers are hedonism (pleasure and the absence of pain, associated with Epicurus), desire satisfaction (getting what you actually want), objective list theories (some goods benefit you whether you want them or not), perfectionism, Aristotle’s eudaimonism (flourishing through virtuous activity) and asceticism (freedom from the pull of appetite). The Buddha’s teaching, which treats craving as a root of suffering and rejects both indulgence and extreme self-denial, offers its own answer. Amartya Sen’s focus on what people are actually able to do and be has shaped recent debate.

Ethics beyond the Western canon

The cards draw on a wider record than the usual line from Aristotle to Kant to Mill:

• Chinese: Confucius and Mencius on character and role, Xunzi on ritual, Mozi’s impartial concern for the benefit of all, Wang Yangming’s unity of knowing and acting, and Dai Zhen. See Chinese philosophy.
• Islamic: the Mu’tazila, al-Ash’ari and al-Māturīdī on reason and revelation, Miskawayh’s ethics of character (akhlāq), and al-Shatibi on the purposes (maqāṣid) of the law: the preservation of life, reason, lineage, property and religion. See Islamic philosophy.
• Indian and Buddhist: Jain non-harm and the Buddha’s teaching on craving and suffering. See Indian and Buddhist philosophy.
• Jewish: Maimonides, physician as well as philosopher, and Emmanuel Levinas, for whom ethics begins in the encounter with another person’s face. See Jewish philosophy.
• African: Ubuntu and the relational view of personhood. See African and Africana philosophy.

These are not footnotes to a European story: Mozi argued for judging acts by their benefit to all more than two thousand years before Bentham. These are the philosophers most often named on the ethics cards:

Examples of ethical questions, and where to start

The quickest way into ethics is through a question you already have an opinion about:

• If an act produces the best outcome, can it be wrong?
• Are some things wrong even when they would do good?
• Should ethics ask what to do, or who to be?
• Could you justify this to everyone it affects?
• Does a company owe anything to anyone but its owners?
• Can you know an act is wrong and be entirely unmoved?

Pick one and notice which rival answer you reject fastest; it is usually the one worth reading most carefully. A good first card is the realism question, because your answer shapes how you read the others:

For reading, the Book corner lists works on ethics with the most approachable first:

These are the latest conversations in the site’s Ethics category and its neighbours. If you have a question of your own, you can ask it.

Where do you stand?

Every question here has serious answers on more than one side. Pick a card, read the rival answers, then say which you find strongest and why. Members ask, reply and take sides; reading is free for everyone.

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