Abstract

We are often unsure about what we ought to do. This can be because we lack empirical knowledge, such as the extent to which future generations will be harmed by climate change. It can also be because we lack normative knowledge, such as the relative moral importance of the interests of present people and the interests of future people. However, though the question of how one ought to act under empirical uncertainty has been addressed extensively by both economists and philosophers---with expected utility theory providing the standard formal framework---the question of how one ought to act under normative uncertainty is comparatively neglected. My thesis attempts to address this gap. In my thesis I develop a view that I call metanormativism: that there are second-order norms that govern action that are relative to a decision-maker's uncertainty about first-order norms. In the first part of the thesis, I defend one specific metanormative view: that under normative uncertainty decision-makers should maximise expected choice-worthiness, treating normative uncertainty analogously with empirical uncertainty. Drawing on the analogy between decision-making under normative uncertainty and social choice theory, I defend this view at length in response to the problem of merely ordinal theories and the problem of intertheoretic value comparisons. In the second part of the thesis, I explore the implications of metanormativism for other philosophical issues. I argue that it has important consequences regarding the theory of rational action in the face of incomparable values, the causal/evidential debate in decision-theory, and our assessment of the value of moral philosophy.