Conspiracy Theory

A conspiracy theory is an explanation for an event or situation that invokes a conspiracy by sinister and powerful groups, often political in motivation, when other explanations are more probable. The term has a negative connotation, implying that the appeal to a conspiracy is based on prejudice or insufficient evidence.
Conspiracy theories resist falsification and are reinforced by circular reasoning: both evidence against the conspiracy and an absence of evidence for it are re-interpreted as evidence of its truth, whereby the conspiracy becomes a matter of faith rather than something that can be proved or disproved. Research suggests that conspiracist ideation—belief in conspiracy theories—may be psychologically harmful or pathological and that it is correlated with psychological projection, paranoia and Machiavellianism. Psychologists attribute finding a conspiracy where there is none to a mental phenomenon called illusory pattern perception.
Historically, conspiracy theories have been closely linked to prejudice, witch hunts, wars, and genocides. They are often strongly believed by the perpetrators of terrorist attacks, and were used as justification by Timothy McVeigh and Anders Breivik, as well as by governments such as Nazi Germany, the Soviet Union, and Turkey. AIDS denialism by the government of South Africa, motivated by conspiracy theories, caused an estimated 330,000 deaths from AIDS, while belief in conspiracy theories about genetically modified foods led the government of Zambia to reject food aid during a famine, at a time when 3 million people in the country were suffering from hunger. Conspiracy theories are a significant obstacle to improvements in public health, encouraging opposition to vaccination and water fluoridation among others, and have been linked to outbreaks of vaccine-preventable diseases. Other effects of conspiracy theories include reduced trust in scientific evidence, radicalization and ideological reinforcement of extremist groups, and negative consequences for the economy.
Conspiracy theories once limited to fringe audiences have become commonplace in mass media, emerging as a cultural phenomenon of the late 20th and early 21st centuries. They are widespread around the world and are often commonly believed, some even being held by the majority of the population. Interventions to reduce the occurrence of conspiracy beliefs include maintaining an open society and improving the analytical thinking skills of the general public.
-https://en.wikipedia.org/wiki/Conspiracy_theory