  Classically, the black hole (BH) horizon is a rigid surface of infinite
redshift; whereas the uncertainty principle dictates that the semiclassical
(would-be) horizon cannot be fixed in space nor can it exhibit any divergences.
We propose that this distinction underlies the BH information-loss paradox, the
apparent absence of BH hair, the so-called trans-Planckian problem and the
recent "firewall" controversy. We argue that the correct prescription is to
first integrate out the fluctuations of the background geometry and only then
evaluate matter observables. The basic idea is illustrated using a system of
two strongly coupled harmonic oscillators, with the heavier oscillator
representing the background. We then apply our proposal to matter fields near a
BH horizon, initially treating the matter fields as classical and the
background as semiclassical. In this case, the average value of the associated
current does not vanish; so that it is possible, in principle, to measure the
global charge of the BH. Then the matter is, in addition to the background,
treated quantum mechanically. We show that the average energy density of matter
as seen by an asymptotic observer is finite and proportional to the BH entropy,
rather than divergent. We discuss the implications of our results for the
various controversial issues concerning BH physics.
