  A possible resolution of the incompatibility of quantum mechanics and general
relativity is that the relativity principle is emergent. I show that the
central paradox of black holes also occurs at a liquid-vapor critical surface
of a bose condensate but is resolved there by the phenomenon of quantum
criticality. I propose that real black holes are actually phase boundaries of
the vacuum analogous to this, and that the Einstein field equations simply fail
at the event horizon the way quantum hydrodynamics fails at a critical surface.
This can occur without violating classical general relativity anywhere
experimentally accessible to external observers. Since the low-energy effects
that occur at critical points are universal, it is possible to make concrete
experimental predictions about such surfaces without knowing much, if anything
about the true underlying equations. Many of these predictions are different
from accepted views about black holes - in particular the absence of Hawking
radiation and the possible transparency of cosmological black hole surfaces.
[To appear in the C. N Yang Festschrift (World Sci., Singapore, 2003).]
