A conspiracy theory is a term that has come to refer to any tentative theory which explains a historical or current event as the result of a secret plot by usually powerful Machiavellian conspirators, such as a "secret team" or "shadow government".

Conspiracy theories are often viewed with skepticism because they contrast with institutional analysis of historical or current events, and are not supported by conclusive evidence. The term is therefore often used dismissively in an attempt to characterize a belief as outlandishly false and held by a person judged to be a crank or a group confined to the lunatic fringe. Such characterization is often the subject of dispute due to its possible unfairness and inaccuracy.

In the late 20th and early 21st century, conspiracy theories have become commonplace in mass media, which has contributed to conspiracism emerging as a cultural phenomenon. Belief in conspiracy theories has therefore become a topic of interest for sociologists, psychologists and experts in folklore.

Terminology

The term "conspiracy theory" may be a neutral descriptor for any conspiracy claim. To conspire means "to join in a secret agreement to do an unlawful or wrongful act or to use such means to accomplish a lawful end." However, conspiracy theory is also used to indicate a narrative genre that includes a broad selection of (not necessarily related) arguments for the existence of grand conspiracies.

The word "theory" is in this usage is informal as in "speculation" or "hypothesis" rather than scientific. Also, the term conspiracy is typically used to indicate powerful figures, often of the Establishment, who are believed to be deceiving the population at large, as in political corruption. Although some conspiracies are not actually theories, they are often labeled as such by the general populace.

The first recorded use of the phrase "conspiracy theory" dates from 1909. Originally it was a neutral term but during the political upheaval of the 1960s it acquired its current derogatory sense. It entered the supplement to the Oxford English Dictionary as late as 1997.

The term "conspiracy theory" is frequently used by scholars and in popular culture to identify secret military, banking, or political actions aimed at stealing power or money from "the people". Less illustrious uses refer to folklore and urban legend and a variety of explanatory narratives which are constructed with methodological flaws. The term is also used in a pejorative sense to automatically dismiss claims that are deemed ridiculous, misconceived, paranoid, unfounded, outlandish or irrational. For example, the term "Watergate conspiracy theory" does not refer to the generally accepted version in which several participants actually were convicted of conspiracy, and others pardoned before any charges were filed, but to alternative and additional theories such as claims that that the source(s) of information called "Deep Throat" was a fabrication 1.