  A non-commuting measurement transfers, via the apparatus, information encoded
in a system's state to the external "observer". Classical measurements
determine properties of physical objects. In the quantum realm, the very same
notion restricts the recording process to orthogonal states as only those are
distinguishable by measurements. Therefore, even a possibility to describe
physical reality by means of non-hermitian operators should \emph{volens
nolens} be excluded as their eigenstates are not orthogonal. Here, we show that
non-hermitian operators with real spectrum can be treated within the standard
framework of quantum mechanics. Furthermore, we propose a quantum canonical
transformation that maps hermitian systems onto non-hermitian ones. Similar to
classical inertial forces this transformation is accompanied by an energetic
cost pinning the system on the unitary path.
