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Spectra of conditionalization and typicality in the multiverse

Azhar, Feraz (2015) Spectra of conditionalization and typicality in the multiverse. Physical Review D, 93 (4).

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Abstract

An approach to testing theories describing a multiverse, that has gained interest of late, involves comparing theory-generated probability distributions over observables with their experimentally measured values. It is likely that such distributions, were we indeed able to calculate them unambiguously, will assign low probabilities to any such experimental measurements. An alternative to thereby rejecting these theories, is to conditionalize the distributions involved by restricting attention to domains of the multiverse in which we might arise. In order to elicit a crisp prediction, however, one needs to make a further assumption about how typical we are of the chosen domains. In this paper, we investigate interactions between the spectra of available assumptions regarding both conditionalization and typicality, and draw out the effects of these interactions in a concrete setting; namely, on predictions of the total number of species that contribute significantly to dark matter. In particular, for each conditionalization scheme studied, we analyze how correlations between densities of different dark matter species affect the prediction, and explicate the effects of assumptions regarding typicality. We find that the effects of correlations can depend on the conditionalization scheme, and that in each case atypicality can significantly change the prediction. In doing so, we demonstrate the existence of overlaps in the predictions of different "frameworks" consisting of conjunctions of theory, conditionalization scheme and typicality assumption. This conclusion highlights the acute challenges involved in using such tests to identify a preferred framework that aims to describe our observational situation in a multiverse.


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Item Type: Published Article or Volume
Creators:
CreatorsEmailORCID
Azhar, Ferazferaz.azhar@alumni.physics.ucsb.edu
Keywords: Anthropic reasoning, conditionalization, typicality, multiverse cosmology
Subjects: Specific Sciences > Physics > Cosmology
Specific Sciences > Probability/Statistics
Depositing User: Dr. Feraz Azhar
Date Deposited: 27 Mar 2016 21:32
Last Modified: 27 Mar 2016 21:32
Item ID: 11996
Journal or Publication Title: Physical Review D
Publisher: American Physical Society
Official URL: http://journals.aps.org/prd/abstract/10.1103/PhysR...
DOI or Unique Handle: https://doi.org/10.1103/PhysRevD.93.043506
Subjects: Specific Sciences > Physics > Cosmology
Specific Sciences > Probability/Statistics
Date: 16 November 2015
Volume: 93
Number: 4
URI: https://philsci-archive-dev.library.pitt.edu/id/eprint/11996

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