Does black hole evaporation imply that physics is nonunitary, and if so, what must the laws of physics look like?

Stephen Hawking's discovery of black hole evaporation has the remarkable consequence that information is destroyed by a black hole, which can only be accommodated by modifying the laws of quantum mechanics. Different attempts to evade the information loss paradox were subsequently suggested, apparently without a satisfactory resolution of the paradox. On the other hand, attempting to include nonunitarity in quantum mechanics might lead to laws predicting observable consequences such as nonlocality or violation of energy–momentum conservation; but it may be possible to circumvent these obstacles. Recent developments seem to require a different view on quantum gravity and suggest that ideas about locality in physics and Hawking's semiclassical approximation are misleading. An accurate description may show unitary evolution and no information loss after all.