The Transcendental Necessity of Morality

David Gauthier tries to defend morality by showing that rational agents would choose to adopt a fundamental choice disposition that permits them to cooperate in prisoner's dilemmas. In this paper, I argue that Gauthier, rather than trying to work out a prudential justification for his favored choice disposition, should opt for a transcendental justification. I argue that the disposition in question is the product of socialization, not rational choice. However, only agents who are socialized in such a way that they acquire a disposition of this type could acquire the capacity to use language. Given the internal connection between language and thought, this means that no agent endowed with such a disposition could rationally choose to adopt another. Thus rational reflection by moral agents upon their own fundamental choice disposition will have no tendency to destabilize it.
"It is a necessary truth that people tend to do what they think they ought to do, for it is a necessary truth that people who occupy a linguistic position which means / ought to do A now , tend to do A. If they did not, the position they occupy could not mean I ought to do A now."
Wilfrid Sellars, "Some Reflections on Language Games."