Anthropic Bias Observation Selection Effects in Science and Philosophy Nick Bostrom
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Blackbeards & Whitebeards Two theories, T1 and T2, each say that there are three room, and the two theories are assigned equal prior probabilities. On T1, two of the rooms contain observers with black beards and the third room contains an observer with white beard. On T2, one room contains a black-bearded observer and the other two contain whitebearded observers. All observers know what color their own beard is (but they cannot see into the other rooms). You find yourself in one of the rooms as a blackbeard. What credence should you give to T1? We can see, by analogy to the Big World cosmology case, that the answer should be that observing that you are a blackbeard gives you reason to favor T1 over T2. But if we use  , we do not get that result.
 In the observer-moment graph of this gedanken (figure 9),  ,  , and  are the blackbeard observer-moments, and e is the information possessed by such an observer-moment (“this observer-moment is a blackbeard”). h is the hypothesis that T1 is true. Given OE&, the observer-moments are partitioned into two reference classes: the blackbeards and the whitebeards (assuming that they are not subjectively distinguishable in any other way than via their beard color). Thus, for example, belongs to the reference class  .
Directory: preprints preprints -> Digitally-assisted discovery and proof preprints -> Reorienting the Logic of Abduction preprints -> Supplementary Material Table 1 Download 9.31 Mb. Share with your friends:
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