  The origin and nature of time in complex systems is explored using quantum
(or 'Feynman') clocks and the signals produced by them. Networks of these
clocks provide the basis for the evolution of complex systems. The general
concept of 'time' is translated into the 'lifetimes' of these unstable
configurations of matter. 'Temporal phase transitions' mark the emergence of
classical properties such as irreversibility, entropy, and thermodynamic arrows
of time. It is proposed that the creation of the universe can be modeled as a
quantum clock. Keywords: the problem of time, the arrow of time, time
asymmetry, the many-body problem, cellular networks, complexity, the
Wheeler-DeWitt equation, quantum cosmology, and instantons.
