The playing field of empirical facts: on the interrelations between moral and empirical beliefs in reflective equilibrium

What exactly is the role of empirical beliefs in moral reflective equilibrium (RE)? And if they have a part to play, can changes in our empirical beliefs effectuate changes in the moral principles we adopt? Conversely, can empirical beliefs be adjusted in light of certain moral convictions? While it is generally accepted that empirical background theory is of importance to the method of wide reflective equilibrium (WRE), this article focuses on a different aspect, namely the role of empirical beliefs that is intrinsic to the coherence relation of moral beliefs in any (narrow or wide) conception of RE. First, it is shown that in the application of RE, empirical beliefs are crucial to the procedure of matching principles to considered judgments. Changes in our empirical beliefs may therefore upset the relevant coherence relation and motivate changes in the moral principles we adopt. This more detailed account of the interplay between empirical and moral beliefs can help evaluate the overall philosophical appeal of RE. Finally, it is argued that, at least in WRE, the relation between empirical and moral beliefs need not be a one-way street, that is, moral convictions can provide us with some epistemic means of adjudicating between competing empirical descriptions of the world.