Rethinking the Anthropic Principle

Abstract The anthropic principle (AP) states that “what we can expect to observe must be restricted by the conditions necessary for our presence as observers”. But the phrase “our presence as observers” cannot be uniquely interpreted in the context of the theories within which AP is meant to be understood and applied: namely, for effective theories. We thus describe and defend a reformulation of AP, which we dub the effective observation principle (EOP). EOP describes what we can expect to observe in physical settings by considering our ‘observational situation’ (and not, specifically, ‘observers’)—understood solely in terms of effective theories.