At another thread, it has been pointed out that Tegmark said the following: Here I want to criticize it. More precisely, I want to show that the suicidal guy cannot be objective about his own chances for survival. Therefore, since his own conclusions cannot be objective, he cannot objectively conclude that his experiment confirms the many-world interpretation. To understand this, for the moment forget about quantum mechanics. Instead, assume that we have a CLASSICAL gun that kills with the probability 50% (classical Russian roulette). We give that gun to a suicide person who wants to kill himself, but we do not tell him what the probability of killing himself is. We ask him to try to kill himself as many times as he wishes and ask him to tell us his conclusions. No matter how many times he tries to kill himself, he will either not exist as a person which can make any conclusion (because he will be dead), or will find out that he survives whenever he tries to kill himself. Thus, he will either conclude nothing, or will highly overestimate the probability of surviving. There is no chance for him to conclude by this experiment that the gun kills in 50% cases. If he will conclude anything, it will be that the probability of surviving is larger than 50%. But we know that this conclusion is wrong. So we must conclude that conclusions about probabilities for surviving found by someone who attempts suicides and survives - are unreliable. So we cannot trust even our own conclusions about our survival probabilities in our own attempted suicides. In this case, we are biased observers who cannot make objective conclusions about probabilities for survival. Subsequently, we cannot make objective conclusions about anything which otherwise could be concluded from those probabilities. So far I was talking about classical probabilities, but quantum probabilities are not much different. If I try suicide many times and I survive each time, I cannot objectively conclude anything about my probabilities for survival. Subsequently, I cannot objectively conclude from that experiment that the many-world interpretation is correct. If I am objective, I know that I am a biased observer, so I know that a naive conclusion that the many-world interpretation seems to be right - is in fact an invalid conclusion. To conclude, objective suicide persons cannot use the quantum suicide experiment to convince themselves about the validity of the many-world interpretation. That's because they are biased observers, so cannot be objective about estimating probabilities. In other words, the first Tegmark's statement above is incorrect.