 The question of the probability of obtaining A makes sense for Lev in world A before he becomes aware of the outcome and for Lev in world B before he becomes aware of the outcome. Both “Lev”s have the same information on the basis of which they should give their answer. According to the probability postulate they will give the same answer: 1/3 (the relative measure of existence of the world \(A)\). Since Lev before the measurement is associated with two “Lev”s after the measurement who have identical ignorance probability concepts for the outcome of the experiment, one can define the probability of the outcome of the experiment to be performed as the ignorance probability of the successors of Lev for being in a world with a particular outcome.