  I provide an alternative way of seeing quantum computation. First, I describe
an idealized classical problem solving machine that, thanks to a many body
interaction, reversibly and nondeterministically produces the solution of the
problem under the simultaneous influence of all the problem constraints. This
requires a perfectly accurate, rigid, and reversible relation between the
coordinates of the machine parts - the machine can be considered the many body
generalization of another perfect machine, the bounching ball model of
reversible computation. The mathematical description of the machine, as it is,
is applicable to quantum problem solving, an extension of the quantum
algorithms that comprises the physical representation of the problem-solution
interdependence. The perfect relation between the coordinates of the machine
parts is transferred to the populations of the reduced density operators of the
parts of the computer register. The solution of the problem is reversibly and
nondeterministically produced under the simultaneous influence of the state
before measurement and the quantum principle. At the light of the present
notion of simultaneous computation, the quantum speed up turns out to be
"precognition" of the solution, namely the reduction of the initial ignorance
of the solution due to backdating, to before running the algorithm, a
time-symmetric part of the state vector reduction on the solution; as such, it
is bounded by state vector reduction through an entropic inequality. PACS
numbers: 03.67.Lx, 01.55.+b, 01.70.+w
