Recently there has been great deal of interest in uncovering the psychological processes of moral judgment. Over the past 10 years, psychologists and neuroscientists have studied the psychology and neurology of moral judgment, and there are now several empirical models of the psychology of moral judgment that attempt to explain these empirical findings. I argue that current empirical models of moral judgment, however, are inadequate, because the psychological processes that they posit cannot explain some important characteristics of other features of our moral psychology. On the other hand, contemporary philosophical accounts of moral judgment do not fare any better, because they are not consistent with recent empirical findings.

My diagnosis for these inadequacies is that contemporary philosophical and empirical models of moral judgment are implicitly committed to what I call the Unity of Process Thesis, which is the claim that all moral judgments are the products of a single psychological process. I argue that the Unity of Process Thesis must be abandoned, because it makes it impossible to account for some important features of our moral psychology. What is needed is a dual-process model of moral judgment, and by drawing on an empirically well-supported dual-process architecture of human judgment, I develop a framework for moral judgment that posits two distinct kinds of moral judgments, intuitive and deliberative, that have very different underlying psychologies that operate in different ways, using different cognitive resources, that are tied to motivation in different ways, and play different roles in our moral psychology. I call this framework the Two Kinds Hypothesis. 

The distinction between intuitive and deliberative moral judging and judgments is quite valuable in developing an overall psychological picture of moral judgment that captures important features of our moral psychology and that is consistent with current accounts of the general architecture of human judgment. This analysis also has upshots in illuminating some debates in metaethics as well, specifically the debate between moral particularists and generalists, and the debate between moral judgment internalists and externalists.