[Drugmachine]

The symmetry still exists in the quantum realm as no such decoherence actually occurs.

Decoherence occurs when there is self-interaction within the macroscopic system. It is a consequence of the high-dimensionality of the Hilbert space of a macroscopic system, leading to the orthogonality (as quantum eigenstates) of classical states. The orthogonality of these states is objective, and therefore there is no subjectivity as to what are the classical states, given the quantum state of the macroscopic system.