Philosophical Studies

, Volume 146, Issue 1, pp 75–92 | Cite as

Parity, incomparability and rationally justified choice

  • Martijn Boot


This article discusses the possibility of a rationally justified choice between two options neither of which is better than the other while they are not equally good either (‘3NT’). Joseph Raz regards such options as incomparable and argues that reason cannot guide the choice between them. Ruth Chang, by contrast, tries to show that many cases of putative incomparability are instead cases of parity—a fourth value relation of comparability, in addition to the three standard value relations ‘better than’, ‘worse than’ and ‘equally good as’. It follows, she argues, that many choice situations in which rationally justified choice seems precluded are in fact situations within the reach of practical reason. This article has three aims: (1) it challenges Chang’s argument for the possibility of parity; (2) it demonstrates that, even if parity would exist, its problematic implications for practical reason would not differ from those of Raz’s incomparability; (3) it discusses the underlying cause of hard cases of comparison: the fact that none of the three standard value relations applies (‘3NT’). It will be shown that the problematic implications for the rational justification of the choice are due to 3NT itself, irrespective of whether 3NT is explained as incomparability or parity.


Parity Incomparability Rationally justified choice 



The research on which this article is based has been made possible by an award of The Arts and Humanities Research Council. I am grateful to Ruth Chang, G. A. Cohen, Joshua Gert, Martha Nussbaum, Wlodek Rabinowicz and an anonymous reviewer for valuable and detailed comments. During a presentation of an earlier version of this paper at the Choice Group of the London School of Economics I got constructive comments which are incorporated in the definitive version.


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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.ChicagoUSA

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