Time-Slice Rationality

Mind 124 (494):449-491 (2015)

Brian Hedden
University of Sydney
I advocate Time-Slice Rationality, the thesis that the relationship between two time-slices of the same person is not importantly different, for purposes of rational evaluation, from the relationship between time-slices of distinct persons. The locus of rationality, so to speak, is the time-slice rather than the temporally extended agent. This claim is motivated by consideration of puzzle cases for personal identity over time and by a very moderate form of internalism about rationality. Time-Slice Rationality conflicts with two proposed principles of rationality, Conditionalization and Reflection. Conditionalization is a diachronic norm saying how your current degrees of belief should fit with your old ones, while Reflection is a norm enjoining you to defer to the degrees of belief that you expect to have in the future. But they are independently problematic and should be replaced by improved, time-slice-centric principles. Conditionalization should be replaced by a synchronic norm saying what degrees of belief you ought to have given your current evidence and Reflection should be replaced by a norm which instructs you to defer to the degrees of belief of agents you take to be experts. These replacement principles do all the work that the old principles were supposed to do while avoiding their problems. In this way, Time-Slice Rationality puts the theory of rationality on firmer foundations and yields better norms than alternative, non-time-slice-centric approaches
Keywords rationality  epistemology  diachronic norms  synchronic norms  bayesianism  conditionalization  reflection
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DOI 10.1093/mind/fzu181
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References found in this work BETA

Epistemology of Disagreement: The Good News.David Christensen - 2007 - Philosophical Review 116 (2):187-217.
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Citations of this work BETA

Accuracy, Coherence, and Evidence.Branden Fitelson & Kenny Easwaran - 2015 - Oxford Studies in Epistemology 5:61-96.
The Uniqueness Thesis.Matthew Kopec & Michael Titelbaum - 2016 - Philosophy Compass 11 (4):189-200.
Internalism Explained.Ralph Wedgwood - 2002 - Philosophy and Phenomenological Research 65 (2):349-369.
Dynamic Permissivism.Abelard Podgorski - 2016 - Philosophical Studies 173 (7):1923-1939.
There Are Diachronic Norms of Rationality.Ulf Hlobil - 2015 - Thought: A Journal of Philosophy 4 (1):38-45.

View all 22 citations / Add more citations

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