This weekend, I’ve been re-thinking some presentational issues with the variant of causal decision theory I develop in this paper (call it ‘manage the improvement news’, or ‘MIN’). Here, I’m going to begin by presenting a general framework for thinking about decision theory (lifted almost entirely from this excellent paper from Konek & Levinstein). Within this framework, we can understand evidential decision theory (EDT) as claiming that the deontic value of an act is given by 1) the act’s evidential impact on 2) axiological value. Standard causal decision theory (CDT) rejects the first component (1) of this theory of deontological value. It denies that you should ‘manage the news’ by incorporating the evidential impact of your selecting the act. MIN, in contrast, retains the first component of EDT’s theory of deontological value but rejects the second (2). It says that the deontic value of an act is given by 1) the act’s evidential impact on 2) its improvement value. MIN thereby agrees with EDT, against CDT, that you should incorporate the evidence provided by an act’s performance into your evaluation of the act. But it disagrees about the underlying evaluation which is to be informed by this evidence.
A foundational assumption in welfare economics is that, if everyone prefers A to B, then A is better than B. This normative claim is called the ‘weak Pareto principle’. At a first glance, this principle can appear unimpeachable. At the very least, it appears to be a sensible principle for policy makers to adopt.
Many of us are also committed to the principle that there are some choices that should be left up to the individual. Even if everyone else prefers that my nose be pierced, if I prefer it unpierced, then it is better for my nose to remain unpierced. A state-of-affairs in which I am compelled to pierce my nose, against my wishes, is worse than a state-of-affairs in which I get to make up my own mind about whether my nose is pierced. And that’s so no matter how many other people would prefer to see me with a pierced nose. Call this committment ‘minimal liberalism’.
In 1970, Amartya Sen produced an amazing result which seems to show that minimal liberalism and the weak Pareto principle are inconsistent with one another. Today I want to rehearse Sen’s result, and introduce an objection to Sen’s way of formalizing ‘minimal liberalism’ first made by Allan Gibbard. I think that Gibbard’s objection teaches us that Sen formulated liberalism incorrectly. However, I’ll conclude by showing that a better formulation of liberalism, one that avoids Gibbard’s objection, is also inconsistent with the weak Pareto principle.