The version of Parfit's account of impartiality that was given in Climbing the Mountain was treated here. In one respect the version that appears in the 2008 version of On What Matters is vulnerable to an objection that was given to the earlier version in a completely unchanged way. This is that Parfit persists in On What Matters in stating the Silver Rule to which Kant states an objection in the Groundwork as if it was equivalent to the Golden Rule, something that he is, it is true, far from alone in doing. Since in the earlier posting I stated at some length the problems I take there to be with this I won't revisit that point here.
The reason why the whole question of the "Golden" Rule is discussed is because of Kant's account of benevolence in the second part of the Groundwork which arises as one of the examples to which the Formula of Universal Law is related. The rule that Kant objects to as a potential alternative to the Formula of Universal Law is rejected by him for three different reasons. Firstly, the rejected rule does not contain the "ground" of duties to oneself, secondly it does not contain the ground of duties "of love" towards others and thirdly it does not contain the ground of "duties" owed to others. The duties of "love" include benevolence and Kant indicates here that the rejected rule does not lead to a duty of benevolence since, on its basis, one can say that one won't help others as one does not require help from them.
The rejected rule is one that Parfit states provides help to others on the basis of the need the others possess and this would be sufficient on its basis to provide an obligatory basis for one helping others. However the rule as Parfit states it is simply that we treat others "as we would want others to treat us" and Kant's point is that if we reject the need for help we can thereby reciprocally deny the need to supply it. This point appears not to be grasped clearly by Parfit. Parfit seems to be arguing, firstly, that the objection misses its target which it does not and secondly that it would apply to FUL which it would not. FUL does not focus on need but on the ground of obligation and the ground of obligation is one that requires universalisation of maxims in accordance with formal rules. These latter do not permit the exemption begged by the one who does not wish to be helped.
Parfit goes on to consider Kant's argument to this effect treating it as a requirement of rationality. When seen this way Parfit appears then to think that the rejected rule would make the same requirement but in doing so he fails to note the reciprocity stated in the rejected rule which is what allows the begged exemption to be stated and which is not involved in FUL in terms of needs. In an attempt to capture some of the force of this idea Parfit restates the rejected rule as follows: "We ought to treat others only in ways in which we would rationally be willing to be treated by others". However this restated form of the rejected rule is one that is then given an objection by Parfit in terms of a different type of begged exemption. Given the reformulation the begged exemption this time does not refer to need but instead is formulated in racist terms with the example being someone who is willing to universally treat those of another race in a way that denies them treatment of a sort that would not be denied to himself. The point that Parfit makes in response is that such a begged exemption misunderstands the reformulated rule which asks us to treat others as we would be treated by them were we in their position.
This additional requirement leads Parfit to restate the rejected rule in a new way: "We ought to treat others only in ways in which we would rationally be willing to be treated, if we were going to be in these other people's positions, and would be relevantly like them". This point brings in a form of imaginative identification and in so doing is meant to counteract the racist move. Having reached this point Parfit assumes that he has reached a formula that is not subject to Kant's objection that the rule be rejected because it does not supply a basis for duties of "love" towards others and turns instead to Kant's objection that the rule does not cover duties "owed" to others. That objection was stated in a form that was appropriate to a duty of right since Kant stated that we need a formula that does not lead - absurdly - to the situation that a convicted criminal can argue with his judge that the judge would not wish to be imprisoned and thus has no right to imprison others. Parfit concedes that certain kinds of view of the rejected rule would have this result. However the right interpretation of the rule would not have this effect and in making this point Parfit revises the rule again: "We ought to treat other people as we would rationally be willing to be treated if we were going to be in the positions of all of these people, and would be relevantly like them". This rule is meant to rule out the absurd result but has the effect that the nature of its application is much harder to see.
The judge is apparently to be asked, in response, to commit the act of imaginative identification not merely of the state of the criminal but of those affected by the criminal's acts. Due to this the judge would not be sympathetic to the criminal's plea. Seen this way, however, it would be the case that the rule has to be viewed as much more extensive than the initial formulation suggested and that might well lead us to the view that it is no longer the same rule that Kant objected to.
The final objection that Kant made to the rejected rule was that it does not disclose the basis of duties to oneself. Parfit first suggests that it is not meant to do this and so this is not an objection to it but concedes that failure to describe such duties might also distort our sense of obligations to others. In order to meet this objection, however, Parfit makes a move that appears questionably consequentialist. It is to reformulate the rejected rule as follows: "We ought to treat everyone as we would rationally be willing to be treated if we were going to be in all of these people's positions, and would be relevantly like them". This response is meant to cover the objection based on duties to oneself by treating oneself, as Mill famously put it, as "one and no more than one" which is precisely the grounds on which Rawls stated that utilitarianism abstracts from the separateness of persons. After all, one is not simply equivalent to others and to treat one in this way is to view obligations as an occasion for maximisation. In fact Parfit does state an awareness of this point but does not attempt to reformulate further the rejected rule in order to meet it.
Rather than do this Parfit looks again at FUL and at Onora O'Neill's view that it is intended to pick out the intuitive idea that we should not treat ourselves as worthy of special treatment. Parfit does specifically mention Rawls' separateness of persons objection and concedes that one person's burdens are not compensated by another's benefits.
Parfit next considers some objections that can be made against universal impartial principles beginning with the Rarity Objection that applies to actions that would be "too rare" to have significant effects on others. This includes cases in which some might be punished for crimes they have not committed on the maxim "let others be punished for my crimes", a maxim that Parfit thinks could pass the Law of Nature test. In appearing to think this Parfit reveals a lack of understanding of the test since the only way this could be taken to be a rule universally applicable is if one could will it applying universally so that others could likewise state it something that would provide a clear contradiction in the will. Parfit seems to think that this is an insufficient response since he thinks this is only a question of a calculated risk not of a real Law of Nature despite affecting to consider the application of the Law of Nature formula. Parfit thus does not really consider the application of the Law of Nature formula in this case at all.
A different objection that Parfit considers is what he terms the High Stakes Objection where performing some kind of act would be undertaken due to it being the case that not to perform would have unusually high consequences for the one in question. So, for example, unless I steal a particular drug from another who also needs it, I'll die. In such a case there is a particularly strong incentive to perform the act in question and this undercuts the appeal to the Law of Nature formula. In fact although it might well be particularly difficult to follow the advice of the Law of Nature formula here this example does not undercut it since, again, application of the maxim in question as a universal law of nature would also render me vulnerable in the same way and thus still be problematic as a universal law to will.
The next point Parfit makes is that the rejected rule is more direct in its impartiality than is the Law of Nature formula. However it is not obvious this is so. The rejected formula requires an act of imaginative identification which fails to include a real sense of agency in it whereas the Law of Nature formula, by contrast, in making its appeal directly to the conditions of agency, could be said to be more direct in its appeal. If what is meant with the claim of indirectness here is that the Law of Nature formula is less directly about the others affected the point is that it is only the ground of the duty, it is not the duty itself which is to the others directly but not directly about them in ground.
The next objection Parfit states is what he calls the Non-Reversibility one which is meant to say that in some cases there is a lack of symmetry between self and others that the Law of Nature formula does not capture. So: "we may know that, even if everyone did these things to others, no one would do these things to us". However this point views the universality tests as if they are meant to seen in terms of actual effects on us rather than as applying to the world in which we would live through the laws that would apply. Such laws would apply to how others related to us in general even if not in specific terms with regard to a given act. Seen like this I fail to see how a non-reversibility claim can be made. Parfit assumes that the racist case cannot be ruled out on the basis of the Law of Nature formula but this is only because he does not think of the racist formula as one that can be used by all races against each other and that this is what is precisely not being willed by the racist (who is therefore "begging an exemption").
Similarly Parfit rightly points out that in many cases privileged people are acting on maxims that allow them to be privileged in appropriate ways. However the point is one not of whether privilege as such is to be viewed as given but of whether behaviour is to rightly based on the ground of duty expressed in the Law of Nature formula. And this does not allow begging of exemption on the part of groups any more than on the part of individuals. So Parfit's examples of treatments of women or slaves are not counter cases to the Law of Nature as treating other groups as inferior on the basis of certain characteristics is not relating to them as rational beings who themselves have the capacity to state and govern themselves by universal laws. It is here that the wrong of such maxims resides.
Parfit fails to grasp this and thus thinks that a different type of rule to the Law of Nature requirement is needed to address specifically disadvantaged groups. This is why he refers to the kinds of imaginative identification that was involved in his reformulation of the rejected rule. This is taken to be preferable to Kant's insistence on a first-personal reference in the Formula of Universal Law. However the point of such reference is to bring out that it is a question of willing that is at issue and this is not involved as clearly in Parfit's reformulation of the "Golden" Rule. Parfit prefers to the Law of Nature formula a version of Moral Belief that is stated on the grounds of a proposal from Thomas Scanlon as follows: "It is wrong for us to act on some maxim unless everyone could rationally will it to be true that everyone believes that such acts are morally permitted". This reference to moral belief has the advantage of bringing in a kind of publicity requirement although the way it does it is not notably preferable to the form of publicity involved in mandating laws to hold as laws of nature. Parfit thinks that the formulation from Scanlon addresses the situation of oppressed groups better but I have seen no reason to accept this.
Parfit's argument concludes with a suggestion that the best way of viewing the situation of rational willing is in terms of a further revision that is expressed as the Kantian Contractualist formula as follows: "Everyone ought to follow the principles whose universal acceptance everyone could rationally will". This formula assimilates Kant to Scanlon but leaves open all the questions about the relationship between the two.