The expressions conspiracy theory, conspiracy theory, conspiracy theory or conspiranoia are used to refer to certain theories that explain an event or a chain of events, commonly, of political, social, economic, religious or historical importance, through action secret of some group. The term conspiracy theory is usually associated specifically with "grand conspiracy theories". The general hypothesis of a conspiracy theory is that certain events, phenomena or occurrences are or have been caused by mysterious hidden conspiracies. According to the Spanish historian Juan Francisco Fuentes: «everything comes from a naive tendency, closely linked to the essence of the world. contemporary, to overvalue the capacity of the human being to come to know everything about what he has already experienced, unless something anomalous prevents him from doing so. According to this perception of the past, incomplete knowledge of a historical episode would only be explained by the intervention of an evil agent that had blinded our gaze or limited our vision of what happened, stealing evidence or leaving false clues along the way. Conspiracy theories should not be confused with true conspiracies ─proven historically and criminologically, punished by criminal laws and court rulings─: although both concepts are closely linked. Some allegations that could be considered conspiracy theories, for example the use of experimental drugs without consent by the CIA, were based on real facts, which could be proven. However, when the expression "conspiracy theory" is used, it is intended to mean that the explanation lacks rational and evidentiary support, although this has been questioned by some authors. Unlike real conspiracies, conspiracy theories should be understood as narratives that share a common narrative structure and with recurring actors.