 Typicality principles have the benefit of making multiverse theories at least in principle testable (Aguirre 2007; Barnes 2017). They are controversial, however, because it is contested whether typicality is always a reasonable assumption (Hartle &amp; Srednicki 2007; Smolin 2007) and because it is difficult to specify with respect to which reference class of observers typicality should be assumed. In practice, observer proxies are chosen such as share of baryon matter clustered in large galaxies (Martel et al. 1998) or entropy gradient (Bousso et al. 2007). These difficulties are exacerbated in cosmological scenarios such as the landscape multiverse in which reference classes of observers that one might reasonably choose are all infinite. The problem of regularizing those infinities corresponds to the so-called measure problem of cosmology, according to some cosmologists “the greatest crisis in physics today” (Tegmark 2014: 314). (See Schellekens [2013: sect. VI.B] for an introduction to the measure problem aimed at physicists, Smeenk [2014] for a philosopher’s sceptical assessment of its solvability, and Dorr &amp; Arntzenius [2017] for a more optimistic perspective.) Friederich (2021: ch. 8) argues that the freedom to choose, for example, an observer proxy and a cosmic measure makes typicality-based predictions from multiverse theories untrustworthy and susceptible to confirmation bias.