Actually, I retract that. The situations are not the same, because in the first case you have information about the system through whether the interference pattern was destroyed or not.
Well that's where it get's complicated though. He talks later about Schrodinger's Cat. That once you start dealing with "wavefunction collapse" you're really including the experimenter in the experiment. Whether they looked at the result or not.
I mean it's a simple thought experiment...
http://www.youtube.com/watch?v=F3viANPhfD0&list=PLA27CEA1B8B27EB67&index=7&feature=plpp_video
The part I am talking about is the discussion around 14.00 minutes, and at 25.00 minutes.
15 min: "The question is whether it left a mark."
25 min: "So if no mark is left that you or anybody else can...
I'm watching Leonard Susskind's online QM lectures, and in it he talks about the double slit experiment. He says that if the particle leaves a "mark", allowing you tell which slit it went through, (for example a "1" vs a "0" on a computer read out) this destroys the interference pattern. But...