Instrumentalism, Objectivity, and Moral Justification

I want to examine critically a certain strategy of moral justification which I shall call instrumentalism. By this I mean the view that a moral theory is rationally justified if the actions, life-plan, or set of social arrangements it prescribes can be shown to be the best means to the achievement of an agent's final ends, whatever these may be. Instrumentalism presupposes a commitment to what I shall call the Humean conception of the self. By this I mean a certain way of conceiving the motivational and structural constituents of the self. Briefly, the self on this conception is motivated by its desires for states of affairs that are temporally or spatiotemporally external to the self. And it is structured by the normative requirements of instrumental rationality: The self is conceived as rationally coherent to the extent that theoretical reason calculates and schedules the satisfaction of as many of its desires as possible, with the minimum necessary costs. The motivational and structural elements of the Humean conception of the self combine to form a familiar explanatory model of human agency: We make sense of an agent's behavior by ascribing to her the desire to achieve the ends that she does in fact achieve, and the theoretically rational belief that, given the information and resources available to her, behaving as she did was the most efficient way to do so. I shall want to argue that to the extent that instrumentalism is successful in providing an objective justification of a moral theory - and I shall contend that it cannot be completely successful - it cannot provide a moral justification. But when we attempt to modify it so as to produce a specifically moral justification, we see that either it is impossible to do this, or else the Humean notion of instrumental rationality is doing no justificatory work.