  Emergence of the classical world from the quantum substrate of our Universe
is a long-standing conundrum. I describe three insights into the transition
from quantum to classical that are based on the recognition of the role of the
environment. I begin with derivation of preferred sets of states that help
define what exists - our everyday classical reality. They emerge as a result of
breaking of the unitary symmetry of the Hilbert space which happens when the
unitarity of quantum evolutions encounters nonlinearities inherent in the
process of amplification - of replicating information. This derivation is
accomplished without the usual tools of decoherence, and accounts for the
appearance of quantum jumps and emergence of preferred pointer states
consistent with those obtained via environment-induced superselection, or
einselection. Pointer states obtained this way determine what can happen -
define events - without appealing to Born's rule for probabilities. Therefore,
Born's rule can be now deduced from the entanglement-assisted invariance, or
envariance - a symmetry of entangled quantum states. With probabilities at hand
one also gains new insights into foundations of quantum statistical physics.
Moreover, one can now analyze information flows responsible for decoherence.
These information flows explain how perception of objective classical reality
arises from the quantum substrate: Effective amplification they represent
accounts for the objective existence of the einselected states of macroscopic
quantum systems through the redundancy of pointer state records in their
environment - through quantum Darwinism.
