I am wondering if there are some views on this. One of the key mysteries of the double slit experiment boils down to when the observation mechanism is placed by one of the slits - and switched on it triggers the change from wave-like outcomes to particle-like outcomes. Is it the observation or the interference of the interaction that causes the collapse of the wave function ? I am sure one could configure the experiment to be such that the observation machine is switched on, "looks" at the slit, but that its result is made unobservable. What happens ?