Different moral theories rely on different assumptions about ethics and human behavior. Some theories, called deontological ethics, emphasize rules and duties as the standard for morality. Others take a teleological approach which stresses the consequences of moral acts. Virtue ethics emphasizes the need to recognize societal pressures in establishing moral standards.
Consequentialist theories are teleological in nature. They find morality in the consequences of actions rather than in the actions themselves. Consequentialist theories, such as Utilitarianism, which was proposed by Jeremy Bentham in the late 18th century and Stuart Mill in the 19th, suggest that the morally correct thing to do is the thing that makes the most people happy. Hedonists, or welfare-utilitarians, focus on net contributions to human welfare. The key to morality, according to this school of thought, is the calculation of net benefit for the group in question.
Deontological theories are best exemplified by Immanuel Kant's Categorical Imperative. Contrary to consequentialist theories, deontological theories focus on the rules that govern behavior rather than on the consequences. Kant argued that moral rules should be universible, that is they should apply equally to all members of society. In that way, people remain the focus of goals and no people's moral rights are sacrificed to ensure the rights of another.
Virtue ethics is the modern version of an Aristotelian ideal. Teleological in nature, followers of virtue ethics believe that reason defines the purpose of human life. The habitual practice of moral and intellectual excellence (virtues) leads to flourishing which is the epitome of human existence. Moral virtues, according to these theories, exist between two vices. For example, courage is seen as the virtue between cowardice and recklessness. Modern virtue ethicists view society as responsible for defining the most relevant ethical standards for the times.