Abstract

In this paper, I criticize the most prevalent positive argument for ethical nonnaturalism, the argument from ethical phenomenology. According to it, nonnatural entities are part of the best explanation of the phenomenology of ethical deliberation; therefore, nonnaturalism is true. The argument from ethical phenomenology blinds out the external, empirically informed perspective on ethical deliberation. I argue that this is unwarranted for general methodological reasons: When starting to investigate any mental process — such as ethical deliberation — it is reasonable to take into account, and try to reconcile, both the internal and the external perspective on the process. This renders the argument from ethical phenomenology methodologically flawed. The problem could be avoided if we already knew, somehow, that external evidence is irrelevant for the nature of ethical entities. Many nonnaturalists believe in this irrelevance because they take ethics to be "autonomous", "just too different", or the like. But the autonomy of ethics must itself be justified in a way that does not solely rely on internal insights — or else we are going in circles. I conclude that solely phenomenology-based arguments for nonnaturalism fail for methodological reasons. Consequently, nonnaturalists need to change their strategies and actively embrace the external perspective.