Individualism is a moral, political or social outlook that stresses human independence and the importance of individual self-reliance and liberty. It opposes most external interference with an individual's choices, whether by society, the state or any other group or institution (collectivism or statism), and it also opposed to the view that tradition, religion or any other form of external moral standard should be used to limit an individual's choice of actions.
Ethical Individualism, then, is the position that individual conscience or reason is the only moral rule, and there is no objective authority or standard which it is bound to take into account. It can be applied to the morality of the Scottish School of Common Sense of the late 18th Century, the autonomous morality of Immanuel Kant, and even ancient Greek Hedonism and Eudaimonism.
Some Individualists are also Egoists (the ethical position that moral agents ought to do whatever is in their own self-interest), although they usually do not argue that selfishness is inherently good. Rather, they would argue that individuals are not duty-bound to any socially-imposed morality, and that individuals should be free to choose to be selfish or not.
Existentialist ethics is also characterized by an emphasis on moral Individualism, especially given its focus on the subjective, personal lives of individual human beings. Existentialism holds that there is no basic and given “human nature” that is common to all people, and so each person must define individually what humanity means to them and what values or purpose will dominate in their lives.
The term "individualism" was first used by French and British proto-Socialists, followers of Saint-Simon (1760 - 1825) and Robert Owen (1771 - 1858), initially as a pejorative term, and mainly in the sense of Political Individualism (see the section below). The 19th Century American Henry David Thoreau is often cited as an example of a committed Individualist. In popular usage, the connotations of "individualism" can be positive or negative, depending on who is using the term, and how.
Political Individualism is the theory that the state should take a merely defensive role by protecting the liberty of each individual to act as he or she wishes, just as long he or she does not infringe on the same liberty of another (essentially the laissez-faire position at the heart of classical Liberalism, Libertarianism and modern Capitalism). It sees itself in fundamental opposition to concepts such as Jean-Jacques Rousseau's "social contract", which maintains that each individual is under implicit contract to submit his own will to the "general will", and in opposition to any collectivist ideology such as Socialism or Communism.
Some Political Individualists hold a view known as Methodological Individualism, that society (and government, for that matter) does not have any existence or meaning above or beyond a collection of individuals, and thus cannot be properly said to carry out actions or possess intentionality. Some even take a radicalist approach called Individualist Anarchism (see Anarchism), which holds that the pursuit of self-interest should not be constrained by any collective body or public authority, refusing to accept even the decisions of democratic government.