 In sum, one approach to anthropic reasoning aims to clarify the rules of reasoning applicable to predictions made by observers in a large or infinite universe. This line of work is motivated by the idea that without such principles we face a severe skeptical predicament, as observations would not have any bearing on the theory. Yet there is still not general agreement on the new principles required to handle these cases, which are of course not scientifically testable principles: they are philosophically based proposals. According to an alternative approach, selection effects can and should be treated within the context of a Bayesian approach to inductive inference (see Neal 2006; Trotta 2008). On this line of thought, “predictions” like those that Bostrom and others hope to analyze play no direct role in the evaluation of cosmological theories, so further principles governing anthropic reasoning are simply not necessary. There is much further work to be done in clarifying and assessing these (and other) approaches to anthropic  reasoning.[47] 