A conspiracy theory is an explanation of an event or situation that invokes a conspiracy without warrant, generally one involving an illegal or harmful act carried out by government or other powerful actors. Conspiracy theories often produce hypotheses that contradict the prevailing understanding of history or simple facts. The term is a derogatory one.

According to the political scientist Michael Barkun, conspiracy theories rely on the view that the universe is governed by design, and embody three principles: nothing happens by accident, nothing is as it seems, and everything is connected. Another common feature is that conspiracy theories evolve to incorporate whatever evidence exists against them, so that they become, as Barkun writes, a closed system that is unfalsifiable, and therefore “a matter of faith rather than proof”.

People formulate conspiracy theories to explain, for example, power relations in social groups and the perceived existence of evil forces. Conspiracy theories have chiefly psychological or socio-political origins. Proposed psychological origins include projection; the personal need to explain “a significant event [with] a significant cause;” and the product of various kinds and stages of thought disorder, such as paranoid disposition, ranging in severity to diagnosable mental illnesses. Some people prefer socio-political explanations over the insecurity of encountering random, unpredictable, or otherwise inexplicable events. Some philosophers have argued that belief in conspiracy theories can be rational.


The Oxford English Dictionary defines conspiracy theory as “the theory that an event or phenomenon occurs as a result of a conspiracy between interested parties; spec. a belief that some covert but influential agency (typically political in motivation and oppressive in intent) is responsible for an unexplained event”, and cites a 1909 article in The American Historical Review as the earliest usage example. As a neutral term, “conspiracy” is derived from Latin con- (“with, together”) and spirare (“to breathe”).

According to John Ayto’s 20th century words, the phrase conspiracy theory was originally a neutral term and only acquired a pejorative connotation in the mid 1960s, implying that the advocate of the theory has a paranoid tendency to imagine the influence of some powerful, malicious, covert agency in events. According to Florida State University professor Lance deHaven-Smith’s 2013 book Conspiracy Theory in America, the phrase conspiracy theory was deployed in the 1960s by the Central Intelligence Agency (CIA) to discredit John F. Kennedy assassination conspiracy theories. However, according to Robert Blaskiewicz, assistant professor of critical thinking at Stockton University and skeptical activist, such claims have existed “since at least 1997”, but due to having recently been promoted by deHaven-Smith, “conspiracy theorists have begun citing this work as an authority”. Blaskiewicz researched the use of the term conspiracy theory and found that it has always been a disparaging term, having been used to describe “extreme hypothesis” and implausible speculation as long ago as 1870.

In response to angry reaction to her use of the term conspiracy theories when describing extreme speculations about the Jonestown massacre, such as claims that the CIA was conducting “mind control experiments”, San Diego State University professor Rebecca Moore said, “They were angry that I had called their version of the truth a conspiracy theory … In many respects, they have a right to be angry. The phrase ‘conspiracy theory’ is not neutral. It is value-laden and carries with it condemnation, ridicule, and dismissal. It is a lot like the word ‘cult,’ which we use to describe religions we do not like.” Moore alternatively describes conspiracy theories as “stigmatized knowledge” or “suppressed knowledge” that are based on a “conviction that powerful individuals are limiting or controlling the free flow of information for nefarious purposes”.

As popular culture

Clare Birchall at King’s College London describes conspiracy theory as a “form of popular knowledge or interpretation”. By acquiring the title ‘knowledge’, conspiracy theory is considered alongside more ‘legitimate’ modes of knowing.

The relationship between legitimate and illegitimate knowledge, Birchall claims, is far closer than common dismissals of conspiracy theory would have us believe. Other popular knowledge might include alien abduction narratives, gossip, some new age philosophies, religious beliefs, and astrology.

Harry G. West wrote, “Conspiracy theorists on the internet are often dismissed as a ‘fringe’ group, but evidence suggests that a broad cross section of Americans today—traversing ethnic, gender, education, occupation, and other divides—gives credence to certain conspiracy theories.” West discusses conspiracy theories as a part of American popular culture, comparing them to hypernationalism and religious fundamentalism.