maybe I should have included the whole quote, but this is regarding the double slit experiment stead delayed choice quantum eraser experiments, where you measure over here but seem to affect over there
> If we place a detector inside or just behind one slit, we can find out whether any given particle goes through it or not. In that case, however, the interference vanishes. Simply by observing a particle's path – even if that observation should not disturb the particle's motion – we change the outcome.
when we place an observer at one of the slits we lose the previously ambiguous diffraction and instead get a clump pattern, but we are definitely probing where it is
> If we place a detector inside or just behind one slit, we can find out whether any given particle goes through it or not. In that case, however, the interference vanishes. Simply by observing a particle's path – even if that observation should not disturb the particle's motion – we change the outcome.
when we place an observer at one of the slits we lose the previously ambiguous diffraction and instead get a clump pattern, but we are definitely probing where it is