Rosemary Rodd on the Original Position

The original position as described by [John] Rawls requires that the original contractors must be all moral agents (otherwise they could not make the decisions needed for the contract), and it is assumed that they will remain so in the real world. I am not sure that this second rule is essential for the idea of a social contract. By analogy with the idea of 'living wills', in which people leave directions about the way they want to be treated if they subsequently lose the ability to make rational decisions, it seems possible that moral agents in the original position might want to safeguard themselves against the possibility of becoming moral patients in the real world. If the contractors do not know whether they may be moral agents or patients later on, they cannot rationally be prepared either to deny the basic rights of moral patients or to commit moral agents to an intolerable burden of ceaseless labour for the welfare of the former. By definition moral patients are not capable of understanding the nature of moral duties so the contractors cannot reasonably decree that the right to basically fair treatment should depend upon acceptance of reciprocal obligation since this would mean giving up their own rights should they happen to be, or to become, moral patients.

(Rosemary Rodd, Biology, Ethics, and Animals [Oxford: Clarendon Press, 1992 (1990)], 241 [footnote omitted])