Humean Externalism and the Argument from Depression

Abstract

Several prominent philosophers have argued that the fact that depressed agents sometimes make moral judgments without being appropriately motivated supports Humean externalism – the view that moral motivation must be explained in terms of desires that are distinct from or “external” to an agent’s motivationally inert moral judgments. This essay argues that such motivational failures do not, in fact, provide evidence for this view. I argue that, if the externalist argument from depression is to undermine a philo-sophically important version of internalism, it must make use of a general assumption about motivational states. However, at a reasonable level of abstraction, the needed assumption also implies that even desires could not be effective sources of motivation. For, just as depressed agents might sometimes lack motivation to act consistently with their moral judgments, they also sometimes lack motivation to pursue their desires. Moreover, the most plausible responses that Humeans can give to this general argument undermine the externalist case against internalism. Thus, there is a deep tension between the argument from depression for externalism and a fundamental Humean commitment.