  "The unambiguous account of proper quantum phenomena must, in principle,
include a description of all relevant features of experimental arrangement"
(Bohr). The measurement process is composed of pre-measurement (quantum
correlation of the system with the pointer variable), and an irreversible
decoherence via interaction with an environment. The system ends up in a
probabilistic mixture of the eigenstates of the measured observable. For the
pre-measurement stage, any attempt to introduce an 'outcome' leads, as we show,
to a logical contradiction, $1=i$. This nullifies claims that a modified
concept of Wigner's Friend, who just pre-measures, can lead to valid results
concerning quantum theory.
