Ideology
An ideology is a collection of ideas or beliefs shared by a group of people. It may be a connected set of ideas, or a style of thought, or a world-view. It was coined by a French philosopher, Destutt de Tracy in 1801/5.
There are two main types of ideologies: political ideologies, and epistemological ideologies. Political ideologies are sets of ethical ideas about how a country should be run. Epistemological ideologies are sets of ideas about the philosophy, the Universe, and how people should make decisions.
There are many different types of ideologies. Communism, socialism, and capitalism are political/economical ideologies.
Many political parties base their political action and program on an ideology. In social studies, a political ideology is a certain ethical set of values, principles, doctrines, myths, or symbols of a social movement, institution, or class which explains how society should work. It offers a political and cultural blueprint for a certain social order. A political ideology largely concerns itself with how to allocate power and to what ends it should be used. Some parties follow a certain ideology very closely, while others may take broad inspiration from a group of related ideologies without specifically embracing any one of them.
Political ideologies have two dimensions:
Goals: how society should work (or be arranged).
Methods: the most appropriate ways to achieve the ideal arrangement.
An ideology is a collection of ideas. Typically, each ideology contains certain ideas on what it considers to be the best form of government (e.g. democracy, theocracy, etc.), and the best economic system (e.g. capitalism, socialism, etc.). Sometimes the same word is used to identify both an ideology and one of its main ideas. For instance, "socialism" may refer to an economic system, or it may refer to an ideology which supports that economic system.
Ideologies also identify themselves by their position on the political spectrum (such as the left, the center or the right), though this is very often controversial. Finally, ideologies can be distinguished from political strategies (e.g. populism) and from single issues that a party may be built around (e.g. legalization of marijuana).
Today, many commentators claim that we are living in a post-ideological age, in which redemptive, all-encompassing ideologies have failed. This is often associated with Francis Fukuyama's writings on "the end of history".
References
Philosophy
Sociology
Political ideologies