Britannica Concise Encyclopedia: ethics
Branch of philosophy concerned with the nature of ultimate value and the standards by which human actions can be judged right or wrong. The term is also applied to any system or theory of moral values or principles. Ethics is traditionally subdivided into normative ethics, metaethics, and applied ethics. Normative ethics seeks to establish norms or standards of conduct; a crucial question in this field is whether actions are to be judged right or wrong based on their consequences or based on their conformity to some moral rule, such as "Do not tell a lie." Theories that adopt the former basis of judgment are called consequentialist (see consequentialism); those that adopt the latter are known as deontological (see deontological ethics). Metaethics is concerned with the nature of ethical judgments and theories. Since the beginning of the 20th century, much work in metaethics has focused on the logical and semantic aspects of moral language. Some major metaethical theories are naturalism (see naturalistic fallacy), intuitionism, emotivism, and prescriptivism. Applied ethics, as the name implies, consists of the application of normative ethical theories to practical moral problems (e.g. abortion). Among the major fields of applied ethics are bioethics, business ethics, legal ethics, and medical ethics.
Columbia Encyclopedia: ethics
in philosophy, the study and evaluation of human conduct in the light of moral principles. Moral principles may be viewed either as the standard of conduct that individuals have constructed for themselves or as the body of obligations and duties that a particular society requires of its members.
Approaches to Ethical Theory
Ethics has developed as people have reflected on the intentions and consequences of their acts. From this reflection on the nature of human behavior, theories of conscience have developed, giving direction too much ethical thinking. Intuitionists (Ralph Cudworth, Samuel Clarke), moral-sense theorists (the 3d earl of Shaftesbury, Francis Hutcheson), and sentimentalists (J. J. Rousseau, Pierre-Simon Ballanche) postulated an innate moral sense, which serves as the ground of ethical decision. Empiricists (John Locke, Claude Helvétius, John Stuart Mill) deny any such innate principle and consider conscience a power of discrimination acquired by experience. In the one case conscience is the originator of moral behavior, and in the other it is the result of moralizing. Between these extremes there have been many compromises.
Meta-ethics
Meta-ethics is concerned primarily with the meaning of ethical judgments and/or prescriptions and with the notion of which properties, if any, are responsible for the truth or validity thereof.
Normative ethics
Normative ethics is the study of ethical norms - moral standards that tell us how to judge right from wrong, or good from bad, and how to live moral lives. This may involve articulating the character or good habits that we should acquire, the duties that we should follow, or the consequences of our actions on ourselves and others.
Descriptive ethics
Descriptive ethics is a value-free approach to ethics which examines ethics not from a top-down a priori perspective but rather observations of actual choices made by moral agents in practice. Some philosophers rely on descriptive ethics and choices made and unchallenged by a society or culture to derive categories, which typically vary by context. This can lead to situational ethics and situated ethics.
http://www.answers.com/ethics