Ethics or moral philosophy is a branch of philosophy that involves systematizing, defending, and recommending concepts of right and wrong conduct. The term ethics derives from the Ancient Greek word ἠθικός ethikos, which is derived from the word ἦθος ethos (habit, "custom"). The branch of philosophy axiology comprises the sub-branches of ethics and aesthetics, each concerned with values.
As a branch of philosophy, ethics investigates the questions "What is the best way for people to live?" and "What actions are right or wrong in particular circumstances?" In practice, ethics seeks to resolve questions of human morality, by defining concepts such as good and evil, right and wrong, virtue and vice, justice and crime. As a field of intellectual enquiry, moral philosophy also is related to the fields of moral psychology, descriptive ethics, and value theory.
Three major areas of study within ethics recognised today are:
- Meta-ethics, concerning the theoretical meaning and reference of moral propositions, and how their truth values (if any) can be determined
- Normative ethics, concerning the practical means of determining a moral course of action
- Applied ethics, concerning what a person is obligated (or permitted) to do in a specific situation or a particular domain of action
Rushworth Kidder states that "standard definitions of ethics have typically included such phrases as 'the science of the ideal human character' or 'the science of moral duty'". Richard William Paul and Linda Elder define ethics as "a set of concepts and principles that guide us in determining what behavior helps or harms sentient creatures". The Cambridge Dictionary of Philosophy states that the word ethics is "commonly used interchangeably with 'morality' ... and sometimes it is used more narrowly to mean the moral principles of a particular tradition, group or individual." Paul and Elder state that most people confuse ethics with behaving in accordance with social conventions, religious beliefs and the law and don't treat ethics as a stand-alone concept.
The word "ethics" in English refers to several things. It can refer to philosophical ethics or moral philosophy—a project that attempts to use reason in order to answer various kinds of ethical questions. As the English philosopher Bernard Williams writes, attempting to explain moral philosophy: "What makes an inquiry a philosophical one is reflective generality and a style of argument that claims to be rationally persuasive." And Williams describes the content of this area of inquiry as addressing the very broad question, "how one should live" Ethics can also refer to a common human ability to think about ethical problems that is not particular to philosophy. As bioethicist Larry Churchill has written: "Ethics, understood as the capacity to think critically about moral values and direct our actions in terms of such values, is a generic human capacity." Ethics can also be used to describe a particular person's own idiosyncratic principles or habits. For example: "Joe has strange ethics."
The English word ethics is derived from an Ancient Greek word êthikos, which means "relating to one's character". The Ancient Greek adjective êthikos is itself derived from another Greek word, the noun êthos meaning "character, disposition".
Meta-ethics asks how we understand, know about, and what we mean when we talk about what is right and what is wrong. An ethical question fixed on some particular practical question—such as, "Should I eat this particular piece of chocolate cake?"—cannot be a meta-ethical question. A meta-ethical question is abstract and relates to a wide range of more specific practical questions. For example, "Is it ever possible to have secure knowledge of what is right and wrong?" would be a meta-ethical question.
Meta-ethics has always accompanied philosophical ethics. For example, Aristotle implies that less precise knowledge is possible in ethics than in other spheres of inquiry, and he regards ethical knowledge as depending upon habit and acculturation in a way that makes it distinctive from other kinds of knowledge. Meta-ethics is also important in G.E. Moore's Principia Ethica from 1903. In it he first wrote about what he called the naturalistic fallacy. Moore was seen to reject naturalism in ethics, in his Open Question Argument. This made thinkers look again at second order questions about ethics. Earlier, the Scottish philosopher David Hume had put forward a similar view on the difference between facts and values.
Studies of how we know in ethics divide into cognitivism and non-cognitivism; this is similar to the contrast between descriptivists and non-descriptivists. Non-cognitivism is the claim that when we judge something as right or wrong, this is neither true nor false. We may for example be only expressing our emotional feelings about these things. Cognitivism can then be seen as the claim that when we talk about right and wrong, we are talking about matters of fact.
The ontology of ethics is about value-bearing things or properties, i.e. the kind of things or stuff referred to by ethical propositions. Non-descriptivists and non-cognitivists believe that ethics does not need a specific ontology, since ethical propositions do not refer. This is known as an anti-realist position. Realists on the other hand must explain what kind of entities, properties or states are relevant for ethics, how they have value, and why they guide and motivate our actions.
Normative ethics is the study of ethical action. It is the branch of ethics that investigates the set of questions that arise when considering how one ought to act, morally speaking. Normative ethics is distinct from meta-ethics because it examines standards for the rightness and wrongness of actions, while meta-ethics studies the meaning of moral language and the metaphysics of moral facts. Normative ethics is also distinct from descriptive ethics, as the latter is an empirical investigation of people's moral beliefs. To put it another way, descriptive ethics would be concerned with determining what proportion of people believe that killing is always wrong, while normative ethics is concerned with whether it is correct to hold such a belief. Hence, normative ethics is sometimes called prescriptive, rather than descriptive. However, on certain versions of the meta-ethical view called moral realism, moral facts are both descriptive and prescriptive at the same time.
Traditionally, normative ethics (also known as moral theory) was the study of what makes actions right and wrong. These theories offered an overarching moral principle one could appeal to in resolving difficult moral decisions.
At the turn of the 20th century, moral theories became more complex and are no longer concerned solely with rightness and wrongness, but are interested in many different kinds of moral status. During the middle of the century, the study of normative ethics declined as meta-ethics grew in prominence. This focus on meta-ethics was in part caused by an intense linguistic focus in analytic philosophy and by the popularity of logical positivism.
In 1971 John Rawls published A Theory of Justice, noteworthy in its pursuit of moral arguments and eschewing of meta-ethics. This publication set the trend for renewed interest in normative ethics.