What, if anything, is wrong with conspiracy theories (CTs)? A conspiracy refers to a group of people acting in secret to achieve some nefarious goal. Given that the pages of history are full of such plots, however, why are CTs often regarded with suspicion and even disdain? According to “particularism,” the currently dominant view among philosophers, each CT should be evaluated on its own merits and the negative reputation of CTs as a class is wholly undeserved. In this paper, I defend a moderate version of “generalism,” the view that there is indeed something prima facie suspicious about CTs, properly defined, and that they suffer from common epistemic defects. To demarcate legitimate theorizing about real-life conspiracies from “mere conspiracy theories” (in the pejorative sense), I draw on a deep asymmetry between causes and effects in the natural world. Because of their extreme resilience to counterevidence, CTs can be seen as the epistemological equivalent of black holes, in which unwary truth-seekers are drawn, never to escape. Finally, by presenting a generic “recipe” for generating novel CTs around any given event, regardless of the circumstances and the available evidence, I rescue the intuitions beneath colloquial phrases like “That's just a conspiracy theory.”