 Unfortunately, concrete multiverse scenarios such as the landscape multiverse are extremely difficult to test, precisely because they entail that different universes exhibit very different conditions. The broad consensus in the literature on multiverse cosmology is that, in order for a multiverse scenario to qualify as empirically confirmed, it must entail that those conditions that we find in our own universe are typical among those found by observers across the multiverse. Widely used formulations of typicality are Vilenkin’s principle of mediocrity (Vilenkin 1995) and Bostrom’s self-sampling assumption (Bostrom 2002). Typicality principles can be regarded as refinements of the anthropic principles (Bostrom 2002) in the form of indifference principles of self-locating belief (Elga 2004): inasmuch as we are ignorant about who and where among observers we are, they recommend to reason as if we were equally likely to be any of the observers who we might possibly be, given our empirical evidence.