What is luck?

The concept of luck plays an important role in philosophical projects in epistemology, ethics, and theory of action. But there is no generally accepted analysis of luck. The purpose of this thesis is to critically assess several popular accounts of luck. I focus on the probability, modal, control, and mixed accounts of luck. I first introduce the philosophical literature on luck and defend various extant accounts of luck from recent arguments by Steven Hales and Jennifer Lackey. I then argue that control accounts of luck fail in all their forms because they are incapable of producing plausible judgements in various cases. I go on to contend that the objective form of the probability account fails because it entails that no events in deterministic worlds are lucky, and that the subjective form fails because it gets cases wrong and cannot show how beings lacking relevant epistemic capacities can be the beneficiaries of luck. Finally, I argue that the standard modal account fails in cases where an event's luckiness is determined by a contrast with what does not happen. I propose a new modal account of luck which avoids this problem. I leave it open whether this modal account, or some suitable mixed account of luck, is preferable.