An ideology is a set of beliefs and values attributed to a person or group of persons, especially as held for reasons that are not purely epistemic. Formerly applied primarily to economic, political, or religious theories and policies, in a tradition going back to Karl Marx and Friedrich Engels, more recent use treats the term as mainly condemnatory.The term was coined by Antoine Destutt de Tracy, a French Enlightenment aristocrat and philosopher, who conceived it in 1796 as the "science of ideas" to develop a rational system of ideas to oppose the irrational impulses of the mob. In political science, the term is used in a descriptive sense to refer to political belief systems.