Here is a definition of conspiracy theories from Wiki that Ron posted:
Conspiracy theory is a term that originally was a neutral descriptor for any claim of civil, criminal, or political conspiracy. However, it has become largely pejorative and used almost exclusively to refer to any fringe theory which explains a historical or current event as the result of a secret plot by conspirators of almost superhuman power and cunning.
Conspiracy theories are viewed with skepticism by scholars because they are rarely supported by any conclusive evidence and contrast with institutional analysis, which focuses on people's collective behavior in publicly known institutions, as recorded in scholarly material and mainstream media reports, to explain historical or current events, rather than speculate on the motives and actions of secretive coalitions of individuals. 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.
According to political scientist Michael Barkun, conspiracy theories once limited to fringe audiences have become commonplace in mass media. He argues that this has contributed to conspiracism emerging as a cultural phenomenon in the United States of the late 20th and early 21st centuries, and the possible replacement of democracy by conspiracy as the dominant paradigm of political action in the public mind. According to anthropologists Todd Sanders and Harry G. West, "evidence suggests that a broad cross section of Americans today…gives credence to at least some conspiracy theories." Belief in conspiracy theories has therefore become a topic of interest for sociologists, psychologists and experts in folklore.
