ar X iv : g r - qc / 9 90 60 42 v 2 1 6 O ct 1 99 9 Cosmological Constant and the Final Anthropic Hypothesis

This principle expresses an observational selection effect: If we have a cosmological theory according to which there are multiple universes or ”domains”, then when thinking about the observational consequences of that theory we have to take into account only those domains in which observers exist. For example, even if the vast majority of domains are inhospitable to life, the theory would predict that we will be observing one of the exceptional domains where conditions appear to be finetuned for life to exist. The only speculative feature of SAP is thus that it is applicable only if there is a multiverse; beyond that it is simply a logical truism, albeit an important one (Leslie 1989). By contrast, the so-called Final Anthropic Principle, introduced in the monograph by Barrow & Tipler (1986), can make no such claim to methodological status. It states that: