A conspiracy theory, according to Merriam-Webster, is “a theory that explains an event or set of circumstances as the result of a secret plot by usually powerful conspirators.” Alternatively, it’s “a theory asserting that a secret of great importance is being kept from the public”; the idea presumably is that insiders have conspired to keep the truth hidden.

Dictionary.com takes a similar approach: “a theory that rejects the standard explanation for an event and instead credits a covert group or organization with carrying out a secret plot” or “a belief that a particular unexplained event was caused by such a covert group.” In all these cases, a conspiracy theory requires a conspiracy to make something happen or to keep something hidden. The cabal has to be hidden and the conspirators powerful; an accusation that some people got together to plan a crime doesn’t count as a conspiracy theory unless the perpetrators are extremely rich or powerful.

The term is increasingly used for assertions that don’t fit those criteria. A while back, I saw a news article calling the assertion that the IRS’s influx of funding would mean more thorough scrutiny of middle-class taxpayers a “conspiracy theory.” The source of the funding wasn’t a secret conspiracy but a highly publicized if misleadingly named bill that Congress passed, the “Inflation Reduction Act,” and it’s no secret that the IRS uses its budget to collect taxes and find underpayment or evasion.

Recently I saw a video about the hypothesis that Jesus had a romantic relationship with Mary Magdalene and perhaps even married her. The narrator referred to it as a “conspiracy theory.” In principle, you could construct a claim that one of the big churches is covering up evidence that he did, and then it would be a conspiracy theory. A book called Holy Blood, Holy Grail claimed exactly that, and Dan Brown mined its premises for the novel The Da Vinci Code. However, the video doesn’t address any such claims; it only addresses the credibility of some ancient documents.

Another claim of a “conspiracy theory” concerns the supposedly imminent “Internet apocalypse.” According to this claim, NASA has issued statements that there will be a Carrington-type event in the next few years that will fry the Internet’s infrastructure and plunge us into a stone age. But that’s the reverse of a conspiracy theory; it’s a claim not that information has been hidden from us, but that we have been warned and aren’t paying attention.

“Conspiracy theory” has often become a label to stick on any claim that someone wants to ridicule. Some conspiracy theories are true, though. It’s widely accepted today that the FBI worked systematically to discredit Martin Luther King and the civil rights movement with false accusations. Claims about deep-rooted conspiracies require strong evidence to back them up, but sometimes the evidence exists.

I keep harping on using terms correctly because misuse not only leads to misinformation but makes it harder to recognize serious claims. If “conspiracy theory” means nothing more than “ridiculous theory,” it’s lost its precision and usefulness. Likewise for any other term that fades into mere name-calling.