Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)




Bradley Nelson Seeman

Loyola University Chicago


The moral philosophies of Allan Gibbard, Christine Korsgaard, and John Post (following Ruth Garrett Millikan's "teleosemantics") each succumb to moral reasons arbitrariness. If a moral philosophy suffers from moral reasons arbitrariness, it fails to establish support relations for moral judgments that uniquely justify those judgments in terms that make essential reference to a person's ability to consider and weigh those support relations in making a moral decision. Moral reasons arbitrariness arises when (1) moral reasons are rooted in factors adventitious to the consideration of support relations, or (2) conflicting moral judgments share the same justificatory grounds as one's own reasons.

Gibbard's noncognitivist norm-expressivism succumbs to moral reasons arbitrariness because it leaves moral reasons as expressions of a human activity of accepting a system of norms. Gibbard's appeals to a sophisticated evolutionary psychology fail to provide the needed constraint on moral reasons, with the result that his moral philosophy fails to provide a satisfactory account of what Gibbard calls the "objective pretensions" of morality.

Korsgaard also fails to avoid moral reasons arbitrariness when she insists that humans confer moral value by reflective endorsement. Korsgaard's account pivots on the role of the maxim in human thought, but she advances two inconsistent accounts of maxims: identity-priority maxims and form-priority maxims. But identity-priority maxims hinge on identities that are not themselves chosen for reasons, while form-priority maxims have a form incapable of constraining moral willing apart from a stable rational identity. Either way, Korsgaard fails to avoid moral reasons arbitrariness.

Post seeks to work the "thin normativity" of Millikan's teleosemantics into a "metaphysics of morals," but encounters fatal difficulties in his attempt to find one bit of our evolved nature that rightly trumps another portion of that same nature. Even if teleosemantics were to provide some crude normativity (as is doubtful), it would be too thin to avoid moral reasons arbitrariness.

In conclusion, the difficulties Gibbard, Korsgaard, and Post have in avoiding moral reasons arbitrariness may be tied to their shared materialism and the problems it creates for giving a satisfactory account of moral reasons.

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