Structural Rationality in Desire

Can desires be irrational?This paper focuses on the possibility that desires might be irrational in virtue of failing to cohere with other mental states of the person in question.Recent literature on structural irrationality has largely neglected structural requirements on desire, and this paper begins to rectify that neglect.This paper endorses various rational requirements on desire, but primarily focuses on the instrumental requirement to desire the means to our ends.It explains how this requirement should be understood, and defends it from numerous objections, such as the worry that there are no real instrumental desires but only combinations of ultimate desires and beliefs (Arpaly and Schroeder 2014; Sinhababu 2017; Smith 2004), and the worry that an instrumental requirement on desire has implausible consequences (Broome 2005; Wedgwood 2011).When might a desire be irrational?One kind of answer to this question might focus on ways in which a desire can fail to track the objective value of its object -e.g.perhaps it is irrational to prefer pain to pleasure.But in this paper I focus on a different kind of answer, one that focuses on ways in which a desire might be in tension with your other attitudes, so that your irrationality consists in a kind of internal incoherence.On some views this is the only kind of irrationality there is, and on other nearby views this is least the only kind of irrationality there is with respect to desire (see e.g.Scanlon 1998, 25 for the first view, and; and perhaps Hume 1738 for the second).But even for those of us who are sympathetic to the existence of multiple kinds of irrationality, internal incoherence is one kind of irrationality, and one worth understanding.The paper is structured as follows: Section 1 introduces the kind of "structural" irrationality that is our focus, and section 2 highlights one plausible structural requirement on desire: the instrumental requirement to desire the means to your ends.Sections 3 to 6 defend the instrumental requirement from various objections, thereby vindicating this canonical rational requirement on desire.Section 7 quickly points out two further points of detail.Section 8 returns to the broader topic and posits four further rational requirements on desire, in addition to the instrumental requirement.As this summary indicates, much of the paper de facto focuses narrowly on the instrumental requirement on desire.This makes sense: it is the most obvious place to begin in investigating rational requirements on desire since it is the canonical such requirement.