 The conclusion, however—that what many still take to be one of the most fundamental principles of quantum theory is violated—is too distasteful for many physicists to swallow, especially those trained in the tradition of particle physics, where unitarity is taken to be inviolate. The sanguine acceptance of the loss of unitarity seems to come mostly from the trust the physicists in question have in general relativity. This raises the question why general relativity ought to be trusted enough in this regime to conclude that unitarity will fail in any deeper quantum theory, but not trusted enough when it comes to the prediction of singularities  (section 2.2)—on  what grounds do they pick and choose when and when not to trust it? This question becomes especially piquant when one considers that loss of unitarity is, on its face, an extraordinarily strong constraint to place on any proposed theory of quantum gravity, especially when it comes from a calculation made in the context of a merely effective and not a fundamental theory, and when it is exactly that still unknown fundamental theory that is supposed to efface singularities. In any event, Manchak and Weatherall (2018) have recently argued that, even if one does accept loss of unitarity—what seems to be a straightforward conclusion of the standard calculations—the state of affairs is still justly called paradoxical. 