The Solipsism of Self-Interest

Abstract

Thomas Nagel argued in The Possibility of Altruism that all reasons for action must be objective, or expressible without reference to the particular person who has them. Anyone who rejects this claim is committed to a form of solipsism. This rules out rational self-interested decision making for anyone who believes in the existence of other minds. This argument was dismantled so decisively by Nicholas Sturgeon in 1974 that it was abandoned by Nagel himself, and no one has taken it up again since. I present a revised conception of Nagel’s ‘impersonal standpoint’, arguing that by acknowledging every mind has its own sense of self, and understanding that the facts about each mind would be accounted for in a complete, objective description of the universe, it must be conceded that no agent can rationally prioritise their own interests where an omniscient impersonal observer, given control over their actions, would have no reason to do so. This is because their sense of self was already accounted for within the objective facts, and so the agent cannot invoke their
experience of it as giving new subjective reason-generating force. As such, Nagel’s argument may be revived, and it may be shown that self-interested reasons for action are incompatible with a rejection of solipsism.