  Relatively simple but apparently novel ways are proposed for viewing three
related subjects: black hole entropy, the black hole information paradox, and
time travel paradoxes. (1) Gibbons and Hawking have completely explained the
origin of the entropy of all black holes, including physical black holes --
nonextremal and in 3-dimensional space -- if one can identify their Euclidean
path integral with a true thermodynamic partition function (ultimately based on
microstates). An example is provided of a theory containing this feature. (2)
There is unitary quantum evolution with no loss of information if the detection
of Hawking radiation is regarded as a measurement process within the Everett
interpretation of quantum mechanics. (3) The paradoxes of time travel evaporate
when exposed to the light of quantum physics (again within the Everett
interpretation), with quantum fields properly described by a path integral over
a topologically nontrivial but smooth manifold.
