Normative ethics is the branch of philosophical ethics that investigates the set of questions that arise when we think about the question “how ought one 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 to determine what proportion of people believe that killing is always wrong, while normative ethics is concerned to determine whether it is correct to hold such a belief. Hence, normative ethics is sometimes said to be 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.
Broadly speaking, normative ethics can be divided into the sub-disciplines of moral theory and applied ethics. In recent years the boundaries between these sub-disciplines have increasingly been dissolving as moral theorists become more interested in applied problems and applied ethics is becoming more profoundly philosophically informed.
Traditional moral theories were concerned with finding moral principles which allow one to determine whether an action is right or wrong. Classical theories in this vein include utilitarianism, Kantianism, and some forms of contractarianism. These theories offered an overarching moral principle to which one could appeal in resolving difficult moral decisions.
In the 20th century, moral theories have become more complex and are no longer concerned solely with rightness and wrongness, but are interested in many different kinds of moral status. This trend may have began in 1930 with D. W. Ross in his book, The Right and the Good. Here Ross agues