A especulação mirabolante de multiversos foi para o saco???

sexta-feira, fevereiro 29, 2008

Title: Bayesian considerations on the multiverse explanation of cosmic fine-tuning
Authors: V. Palonen
Categories: physics.data-an gr-qc hep-th
Comments: 14 pages, 2 figures

The fundamental laws and constants of our universe seem to be finely tuned for life. Alongside design, the various multiverse hypotheses have been popular explanations for the fine tuning. This paper focuses on the multiverse explanations and reviews the four main suggestions on how inference should be done in the presence of possible multiple universes and observer selection effects. Previously unnoticed conditional dependencies of the propositions involved, results from Bayesian belief networks, and basic identities from probability theory are used to tease out the proper style of inference. In the case of cosmic fine-tuning, information about the observation is not independent of the hypothesis. It follows that the observation should be used as data when comparing hypotheses. Hence the approaches that use the observation only as background information are incorrect. It is also shown that in some cases the self sampling assumption by Bostrom leads to probabilities greater than one, leaving the approach inconsistent. The "some universe" (SU) approach is also found wanting and several reasons are given why the "this universe" (TU) approach
seems to be correct. The converse selection effect -requirement for SU by White is clarified by showing formally that the converse condition leads to SU and its absence to TU. The overall result is that because multiverse hypotheses do not predict the fine-tuning of this universe any better than a single universe hypothesis, the multiverse hypotheses fail as explanations for cosmic fine-tuning. Conversely, fine-tuning data does not support the multiverse hypotheses.
PDF aqui. [181 KB] http://arxiv.org/abs/0802.4013