Treating belief in conspiracy theories as a failure of reasoning misdescribes what is usually happening. Conspiracies occur; institutions have lied; and a person who has been deceived by an authority and adjusts their expectations accordingly is doing something epistemically respectable, even when the conclusion they reach is false. What distinguishes the pathological cases is not the suspicion but its unfalsifiability — the readiness to treat every disconfirming fact as further evidence of the cover-up — and that feature is a property of the belief's structure rather than of the believer's intelligence, which is why correction by information so reliably fails. Approaches that begin from an assumption of stupidity have a poor record, and the assumption is doing more work in the analysis than the evidence supports. Explanations that flatter the explainer tend to survive rather longer than the evidence for them.