  Decoherence shows how the openness of quantum systems -- interaction with
their environment -- suppresses flagrant manifestations of quantumness.
Einselection accounts for the emergence of preferred quasi-classical pointer
states. Quantum Darwinism goes beyond decoherence. It posits that the
information acquired by the monitoring environment responsible for decoherence
is disseminated, in many copies, in the environment, and thus becomes
accessible to observers. This indirect nature of the acquisition of information
by observers who use the environment as a communication channel is the
mechanism through which objective classical reality emerges from the quantum
substrate: States of the systems of interest are not subjected to direct
measurements (hence, not perturbed) by the agents acquiring information about
them. Thus, they can exist unaffected by the information gained by observers.
