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

Brian Hedden
Australian National University
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
Categories (categorize this paper)
DOI 10.1093/mind/fzu181
Edit this record
Mark as duplicate
Export citation
Find it on Scholar
Request removal from index
Revision history

Download options

PhilArchive copy

 PhilArchive page | Other versions
External links

Setup an account with your affiliations in order to access resources via your University's proxy server
Configure custom proxy (use this if your affiliation does not provide a proxy)
Through your library

References found in this work BETA

Reasons and Persons.Derek Parfit - 1984 - Oxford University Press.
Philosophical Papers.David K. Lewis - 1983 - Oxford University Press.
Reasons and Persons.Joseph Margolis - 1986 - Philosophy and Phenomenological Research 47 (2):311-327.
Epistemology of Disagreement: The Good News.David Christensen - 2007 - Philosophical Review 116 (2):187-217.
Reflection and Disagreement.Adam Elga - 2007 - Noûs 41 (3):478–502.

View all 58 references / Add more references

Citations of this work BETA

The Uniqueness Thesis.Matthew Kopec & Michael G. Titelbaum - 2016 - Philosophy Compass 11 (4):189-200.
Uniqueness and Metaepistemology.Daniel Greco & Brian Hedden - 2016 - Journal of Philosophy 113 (8):365-395.
The Structure of Epistemic Probabilities.Nevin Climenhaga - 2020 - Philosophical Studies 177 (11):3213-3242.
Accuracy, Coherence and Evidence.Branden Fitelson & Kenny Easwaran - 2015 - Oxford Studies in Epistemology 5:61-96.

View all 47 citations / Add more citations

Similar books and articles

Diachronic Rationality.Patrick Maher - 1992 - Philosophy of Science 59 (1):120-141.
Intention Rationality.Michael E. Bratman - 2009 - Philosophical Explorations 12 (3):227-241.
Introduction: Aspects of Rationality.Alfred R. Mele & Piers Rawling - 2004 - In Alfred R. Mele & Piers Rawling (eds.), The Oxford Handbook of Rationality. Oxford University Press.
Rationality and the Emotions.Jon Elster - 1996 - Economic Journal 106:1386-97.
Diachronic Dutch Book Arguments.Anna Mahtani - 2012 - Philosophical Review 121 (3):443-450.
Constitutivism and the Inescapability of Agency.Luca Ferrero - 2009 - Oxford Studies in Metaethics 4:303-333.
Unifying the Requirements of Rationality.Andrew Reisner - 2009 - Philosophical Explorations 12 (3):243-260.
Distorted Reflection.Rachael Briggs - 2009 - Philosophical Review 118 (1):59-85.
Dutch Strategies for Diachronic Rules: When Believers See the Sure Loss Coming.Brad Armendt - 1992 - PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association 1992:217 - 229.


Added to PP index

Total views
1,164 ( #3,851 of 2,440,216 )

Recent downloads (6 months)
84 ( #7,546 of 2,440,216 )

How can I increase my downloads?


My notes