Anthropic Bias Observation Selection Effects in Science and Philosophy Nick Bostrom
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Case 3. The messenger decided to travel to the realm of physical existence and look for some universe that contains observers. He found  , and reports this back to you.
Does this provide you with any evidence for hM? It depends. If you knew (call this Case 3a) that God had set out to create at least one observer-containing universe, then the tiding that is actual does not give any support to hM (unless you know that has some special feature). Because then you were guaranteed to learn about the existence of some observer-containing universe or other and learning that it is does not give any more evidence for hM than if you had learnt about some other universe instead. The messenger’s tidings T contain no relevant new information. The probably you assign to hM remains unchanged. In Case 3a, therefore, P(hM|T) = P(hM).
But there is second way of specifying Case 3. Suppose (Case 3b) that God did not set out especially to create at least one observer-containing universe, and that for any universe that He created there was only a fairly small chance that it would be observer-containing. In this case, when the messenger reports that God created the observer-containing universe , you get evidence that favors hM. For it is more probable on hM than it is on ¬hM that one or more observer-containing universes should exist (one of which the messenger was then bound to bring you news about). Here, we therefore have P(hM|T) > P(hM).
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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