Tuesday, 20 October 2009
Cosmology and Inductive Inference: A Bayesian Failure
John D. Norton, University of Pittsburgh , Center for Philosophy of Science, Department of History & Philosophy of Science
12:05 pm, 817R Cathedral of Learning

Abstract: Probabilistic representation is unable to separate cleanly neutral support from disfavoring evidence (or ignorance from disbelief).  Since this separation is essential for the analysis of evidential relations in cosmology in the context of multiverse and anthropic reasoning, the use of probabilistic representations may introduce spurious results stemming from its expressive inadequacy. That such spurious results arise in the Bayesian “doomsday argument” is shown by a reanalysis that employs fragments of inductive logic able to represent evidential neutrality. Similarly, the mere supposition of a multiverse is not yet enough to warrant the introduction of probabilities without some analog of a randomizer over the multiverses. The improper introduction of such probabilities is illustrated with the “self-sampling assumption.