> Yes, this is similar to the "Wigner's friend" thought-experiment.
Wigner later (1983) changed opinion and wrote
that decoherence forbids superposition of states like
c1 |s 1> |friend 1> + c2 |s 2> |friend 2>
After that in QM the "conscious" being - i.e. the "friend"
who tells that he already "knows" whether the outcome is
|s 1> or |s 2> - plays no role. Von Neumann, London,
Bauer, Wigner thought (and many more still think) that
consciousness was able to "collapse" a superposition
(E.P.W., Collected Papers, VI, pages 225-244)
s.
