By and large, whenever we hear that someone believes that an event came about due to a conspiracy we think that they are somewhat naively believing in a Conspiracy Theory and that they have made some â€˜wrong moveâ€™ epistemically. We do, I think, treat the term â€˜Conspiracy Theoryâ€™ in a pejorative sense. The Inference to Conspiracy, whereby we explain events with reference to a Conspiracy, underlies the intuition that Conspiracy Theories, per se, are bad. It is because we take the Inference to Conspiracy to be (usually) unwarranted that we treat the term Conspiracy Theory as a pejorative.The Inference to Conspiracy is a version of the Inference to Any Old Explanation, the so-called â€˜Just Soâ€™ Fallacy. However, for a proper understanding of how and why the Inference to Conspiracy should be treated, prima facie, as a fallacy we should admit to two senses of the term ‘Conspiracy Theory.’The first is what I call the ‘General.’ The term `Conspiracy Theory’ is sometimes used in connection with any event with an associated Conspiracy. We can tell two different Conspiracy Theory stories about the assassination of JFK. One is the Official View which is that it was a conspiracy on the part of the KGB and Lee Harvey Oswald whilst the other is the Unofficial View, that the American Government and the CIA conspired to kill President Kennedy. Thus some Conspiracy Theories are warranted, and we recognise this fact by admitting to there being explanations of events in History that rest upon the fact that cabals conspired and that many of the theories about such conspiracies, such as those surrounding the Trotksy Trials of the 1930s, turned out to be good.In this version the pejorative form of â€˜Conspiracy Theoryâ€™ is any explanation that makes reference to a Conspiracy that is not taken to be the best inference. If Lee Harvey Oswald and agents of the KGB conspired to kill President Kennedy, then surely this is an example of a conspiracy. However, this is not contentious; this is an accepted part of the historical record. It is the Official View; the view formed by the Warren Commission who investigated the assassination. The Unofficial View, the Conspiracy Theory in the pejorative sense, is that the American Government was somehow responsible for the death of JFK.Official and Unofficial are not the most helpful of terms here. The Official View here means literally that; it is the view held by the officials, the supposed experts or authorities invested by the Government of the United States of America, to investigate the assassination of President Kennedy. This Official View also happens to be the explanation accepted by most of the researchers and historians of the period. Sometimes, however, the Official View will not accord with the work of historians and researchers and the Official View may not be the consensus view at all. This leads me on to my second sense of the term â€˜Conspiracy Theory,â€™ the Unofficial.Sometimes the term `Conspiracy Theory’ is only used in connection with an explanation that runs counter to the Official View [Needs a rewrite; really we should be talking about consensus views rather than in the terminology of the Official. This might just be because we need to have chapters 1 and 2 finished before this section can be truly tight]. The Official View is the explanation of the event that we take to be the best; it is the Inference to the Best Explanation. Sometimes we do not refer to such Official Views as Conspiracy Theories; the attacks of 9/11 were of a conspiratorial kind but the purported explanation which implicates Al Qaeda in the attack is not labeled a Conspiracy Theory. In this sense we reserve the label ‘Conspiracy Theory’ for the claim that the attacks were perpetrated by the American Government. This explanation, unwarrantedly referring as it does to conspiratorial activity is labeled a Conspiracy Theory as it goes against the Official View, which is to say that it flies against the best inference and is an example of an Inference to Any Old Explanation.Take the Trotsky Trials. In the 1930s the Russian State places Trotsky and his associates on trial for treason. Whilst the defendants protest their innocence the trials render guilty verdicts and they are sentenced to death. Some people are suspicious; the trials may well have been orchestrated show trials, rendering guilty verdicts because that is what Joseph Stalin wanted, but the Kremlin denies this and claims proper judicial procedure was adhered to. American and Britain agree but the Dewey Commission, who investigate the trials, comes to another verdict; the trials were for show after all and Trotsky and his comrades could never have had any other verdict than guilty. At this time, 1938, the proponents of the Dewey Commission are labelled â€˜Conspiracy Theoristsâ€™ and yet, in 1952, they were vindicated. The trials had been for show, the Official View was a cover-up and what was taken to be a Conspiracy Theory was actually the explanation after all.