Brian Hedden defends a radical view about the relationship between rationality, personal identity, and time. On the standard view, personal identity over time plays a central role in thinking about rationality. This is because, on the standard view, there are rational norms for how a person's attitudes and actions at one time should fit with her attitudes and actions at other times, norms that apply within a person but not across persons. But these norms are problematic. They make what you rationally ought to believe or do depend on facts about your past that aren't part of your current perspective on the world, and they make rationality depend on controversial, murky metaphysical facts about what binds different instantaneous snapshots (or 'time-slices') into a single person extended in time. Hedden takes a different approach, treating the relationship between different time-slices of the same person as no different from the relationship between different people. For purposes of rational evaluation, a temporally extended person is akin to a group of people. The locus of rationality is the time-slice rather than the temporally extended agent. Taking an impersonal, time-slice-centric approach to rationality yields a unified approach to the rationality of beliefs, preferences, and actions where what rationality demands of you is solely determined by your evidence, with no special weight given to your past beliefs or actions.

About the Author
Brian Hedden was an undergraduate at Princeton University, graduating with a degree in philosophy in 2006. He received his doctoral degree from the Massachusetts Institute of Technology in 2012, after which he was a junior research fellow at Oxford University until 2014. Since 2015 he has been a lecturer at the University of Sydney.

Reviews
The book is a masterful work of analystic philosophy. * Matthew Kopec, Australasian Journal of Philosophy *
This is a well-written, ambitious book that ties disparate strands of philosophy together into a complete picture of what is required for an agent to be ... To my knowledge, this is something only Derek Parfit has been successful at tackling thus far. In general, the book is knowledgeable and an interesting read ... the book is recommended reading for anyone interested in the connections between rationality and personal identity, and it is written in a way that makes it accessible to pretty much anyone interested in the topic. * Heidi Savage, Notre Dame Philosophical Reviews Online *



Book Information
ISBN 9780198732594
Author Brian Hedden
Format Hardback
Page Count 220
Imprint Oxford University Press
Publisher Oxford University Press
Weight(grams) 488g
Dimensions(mm) 243mm * 167mm * 21mm