The Irreducibility of Personal Obligation

It is argued that claims about personal obligation (of the form “s ought to ϕ”) cannot be reduced to claims about impersonal obligation (of the form “it ought to be the case that p”). The most common attempts at such a reduction are shown to have unacceptable implications in cases involving a plurality of agents. It is then argued that similar problems will face any attempt to reduce personal obligation to impersonal obligation.