William MacAskill

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.

The cofounder of the Effective Altruism movement presents a counterintuitive approach anyone can use to make a difference in the world. While studying philosophy at Oxford University and trying to work out how he could have the greatest impact, William MacAskill discovered that most of the time and money aimed at making the world a better place achieves little. Why? Because individuals rarely have enough information to make the best choices. Confronting this problem head-on, MacAskill developed the concept of effective altruism, a scientific, data-driven approach to making a difference that operates by asking these five questions: How much will this action improve others' lives? Is this the most effective action I can take? How useful is my contribution, given what others are already doing? What will happen if I don't do it? What are the chances of success, and how good would success be? Applying these principles, he demonstrates that many of our assumptions about doing good are misguided: he argues that one can potentially save more lives by working on Wall Street than as a heart surgeon, that cancer charities are not the best use of money, and that buying sweatshop-produced goods is a form of ethical consumption. MacAskill challenges us to think differently but argues that if we set aside our biases and rely on evidence and careful reasoning, each of us can make a tremendous difference.

In this paper I propose an approach to decision theory that I call metanormativism, where the key idea is that decision theory should take into account decision-theoretic uncertainty. I don’t attempt to argue in favor of this view, though I briefly offer some motivation for it. Instead, I argue that if the view is correct, it has important implications for the causal versus evidential decision-theory debate. First, it allows us to make rational sense of our seemingly divergent intuitions across the Smoking Lesion and The Psychopath Button cases. Second, it generates strong new arguments for preferring the causal approach to decision-theory over the evidential approach.

In “Rejecting Ethical Deflationism,” Jacob Ross argues that a rational decision maker is permitted, for the purposes of practical reasoning, to assume that nihilism is false. I argue that Ross’s argument fails because the principle he relies on conflicts with more plausible principles of rationality and leads to preference cycles. I then show how the infectiousness of nihilism, and of incomparability more generally, poses a serious problem for the larger project of attempting to incorporate moral uncertainty into expected value maximization style reasoning.

Some philosophers have recently argued that decision-makers ought to take normative uncertainty into account in their decisionmaking. These philosophers argue that, just as it is plausible that we should maximize expected value under empirical uncertainty, it is plausible that we should maximize expected choice-worthiness under normative uncertainty. However, such an approach faces two serious problems: how to deal with merely ordinal theories, which do not give sense to the idea of magnitudes of choice-worthiness; and how, even when theories do give sense to magnitudes of choice-worthiness, to compare magnitudes of choice-worthiness across different theories. Some critics have suggested that these problems are fatal to the project of developing a normative account of decision-making under normative uncertainty. The primary purpose of this article is to show that this is not the case. To this end, I develop an analogy between decision-making under normative uncertainty and the problem of social choice, and then argue that the Borda Rule provides the best way of making decisions in the face of merely ordinal theories and intertheoretic incomparability.