Benja: Good explanation! Intuitively, it seems to me that your argument holds if there are Tegmark IV branches with different physical laws, but not if whether the LHC would destroy Earth is fixed across the entire multiverse. (Only in the latter case, if it would destroy the Earth, the objective frequency of observations of failure—among observations, period—would be 1.)
Benja: Good explanation! Intuitively, it seems to me that your argument holds if there are Tegmark IV branches with different physical laws, but not if whether the LHC would destroy Earth is fixed across the entire multiverse. (Only in the latter case, if it would destroy the Earth, the objective frequency of observations of failure—among observations, period—would be 1.)