The basic moralist response to Williams' integrity objection
In the last section, we interpreted Williams' integrity objection as an argument for the separation of two viewpoints. In short, the utilitarian impartial viewpoint cannot make sense of the value of integrity as it does make sense in the internal viewpoint. There is, however, a basic response to this argument: the separation of two viewpoints is datum and the impartial viewpoint should guide our contingent internal viewpoints (Brink [1986] p.432). According to this response, the point of moral theories is to govern our mutually conflicting internal viewpoints by the impartial standard. Hence, Williams argument for the separation of two viewpoints seems to be a non-starter. Rather, he needs to show that the internal viewpoints are prior to the impartial viewpoint against moralists.
Case for moralists: Nazi officer's integrity
According to moralists, our internal viewpoints are subjective, non-moral and mutually-conflicting. To see this, we can look at the case which Williams himself raised (WME:213). A Nazi officer is about to command the execution of a Jewish person but is offered a bribe in exchange for cancelling the execution. Here, though he will show his integrity by declining the bribe, his integrity is morally unacceptable. As this case shows, integrity can be morally unacceptable, and, thus, we seem to need an impartial viewpoint to guide our internal viewpoints.
Williams-style reply to moralist response
Unlike moralists who assert that impartial viewpoint is primary in ethics, Williams seemed to suggest that the internal viewpoint (the inside view from one's disposition) is primary in ethics (PHD: 74-5). In other words, ethical values make sense in internal viewpoints. On the other hand, if certain moral values obtain solely in the impartial point of view and do not obtain in the internal viewpoints, they does not make sense as values. Williams says: "Life has to have substance if anything is to have sense, including adherence to the impartial system; but if it has substance, then it cannot grant supreme importance to the impartial system".
Williams' argument for the primacy of internal viewpoint: Internalism about reason
Williams proposes an argument for the primacy of internal viewpoint in ethics: an agent has reason to act only if there is a sound deliberative route to one's motivations. An agent's reason has to be connected to her motivations (internalism about reason). If not, she does not have reason to follow that. Utilitarianism and impartial moral theories are, however, committed to externalism about reason. While they suppose that the impartial viewpoint can guide us regardless of subjective motivations (internal viewpoints), Williams' argument shows otherwise.
Reconsidering Nazi officer's integrity
Indeed, the impartial viewpoint itself does not have any effect on the Nazi officer. The moral theories impose on him no reason to be moral, as he does not care about morality. If we, as we do, want to change the officer's value and integrity, we need to change his internal viewpoint instead of polishing impartial moral theories.
Summary of this section
The basic moralist response to Williams' integrity objection has been that the impartial viewpoint should guide the internal viewpoint, and, therefore, the separation of two viewpoints is not a problem for the utilitarian point of view. However, Williams can contend that the internal viewpoint is primary in ethics. As shown in his reason internalism, the impartial viewpoint itself cannot guide our internal viewpoints.