The title of this thesis is also its question: what is a hard choice? I start addressing this in chapter 1 by arguing that at the most general level, a hard choice is a situation that condemns an agent to failure. Specifically, hard choices condemn an agent to failure because rational agents must act in a way that can be justified, but they cannot do so when facing a hard choice. They cannot do so because, in a hard choice, an agent's given reasons for action will fail to determine what, all things considered, the agent ought to do. Subsequent chapters of this thesis develops this view in more detail.
Chapter 1* presents the formal framework that will be used in this thesis. It argues that there is an important sense in which the standard theory of rational choice needs to be reformulated in order to present a sound theory of hard choices. Chapter 2 argues that leading positions on hard choices that can be found in the literature provide an inadequate understanding of them. The argument presented to defend my claims will refer directly or indirectly to the fairly intuitive idea that a situation where a best---or optimal---alternative exists does not constitute a hard choice. That is, optimization implies rationality.
Chapter 3 asks the converse: does rationality imply optimization? The chapter defends two claims. First, if you cannot optimize because of incompleteness of the binary preference or value relation that you hold, then you are facing a hard choice. Second, if you cannot optimize because the binary preference or value relation that you hold is cyclic, then you are not facing a hard choice. Chapter 4 doubles down on this claim by characterizing this understanding of a hard choice. More specifically, chapter 4 presents a systematic analysis of the axiomatic structure of hard choices with the help of the theory of rational choice. This is the most formal chapter of the thesis, and it presents joint work undertaken with Prof. Martin van Hees and Dr. Roland Luttens.
Chapter 5 also presents joint work with Prof. Martin van Hees and Dr. Roland Luttens. This chapter scrutinizes the most famous existence argument for hard choices, to wit: the small-improvement argument, and argues that it fails to establish the existence of hard choices. Chapter 6 will be concerned with extending the analysis of hard choices that has been presented in the preceding chapters. Specifically, observe that the claims in the preceding chapters have been articulated and defended by presupposing the existence of an all things considered binary relation that describes an agent's preferences or values. Chapter 6, however, will present an analysis of hard choices that does not require presupposing such a binary relation. A Coda motivates the possibility of another extension: collective hard choices.
