  It is well known that the pointer state |{\Phi}> resulting from the von
Neumann measurement of a projection operator A performed upon an ensemble of
quantum systems in the preselected state |{\psi}> depends upon A|{\psi}>. Here
it is shown that the pointer state |{\Psi}> obtained from such a measurement
performed upon an ensemble that is also postselected depends upon the weak
value of A - regardless of the measurement interaction strength. It is also
found that, while the spatial distribution of |{\Psi}> exhibits interference,
the idempotency of A prohibits interference in that of |{\Phi}>. This is
explained in terms of welcher Weg information.
