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Realism, Convergence, and Additivity

Published online by Cambridge University Press:  28 February 2022

Cory Juhl  and
Kevin T. Kelly
Cory Juhl
Affiliation:
University of Texas, Austin
Kevin T. Kelly
Affiliation:
Carnegie-Mellon University
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Extract

In one version of the debate between scepticism and scientific realism, the sceptic denies and the realist affirms the ability of science to home in on the unknown truth. Germane to this debate is the familiar claim that probabilistic updating by Bayesian conditionalization will almost surely arrive at the truth so long as one does not “close the door” on a hypothesis by assigning it probability zero. In this paper, we observe, on behalf of the sceptic, that there exists a coherent agent who in fact fails on an uncountable set of possible worlds to find the truth about a simple, universal hypothesis H even though he “keeps the door open” concerning H until H is logically refuted and even though there is a trivial, logically driven method that converges to the truth about H no matter what; that nonetheless, this agent “almost surely” arrives at the truth in the usual, Bayesian sense because the uncountable set of circumstances in which he fails is assigned probability zero by the agent; and that the guarantee that the set of all circumstances in which the agent fails has probability zero hinges on the axiom of countable additivity.

Type
Part V. Realism and its Guises
Information
PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association , Volume 1994 , Issue 1: Volume One: Contributed Papers 1994 , 1994 , pp. 181 - 189
Copyright
Copyright © 1994 by the Philosophy of Science Association

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Footnotes

1

Cory Juhl's contribution to this work was funded by a grant from the University Research Institute at the University of Texas at Austin.

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