史密斯的規範理由觀

Abstract

Michael Smith認為，在後設倫理學的討論中，為了兼顧道德的客觀性與實踐力，而使得三個符合常民直覺的相關道德立場，無法同時成立，此為Smith所謂「道德難題」。這三個立場分別是認知主義、判斷內在論與休謨式動力理論。難題的解決關鍵在於，將行動的理由區分為動機理由與規範理由，並且提出一套對於規範理由的分析。Smith則是以「完全理性者」為核心概念，建構他的規範理由觀。而在Smith刻劃下的完全理性者，具備最融貫的欲望集合，因而能夠兼顧道德的規範力與實踐力。然而，仔細探究欲望集合之「融貫性」概念的話，將會發現，完全理性者的模型，不論是在道德的規範力還是實踐力面向，均不夠有說服力。換言之，Smith的規範理由觀未能如他所願地兼顧道德的客觀性與實踐力，以致於他是否成功解決難題，是令人質疑的。

According to Michael Smith, folk attitudes suggest that morality are both objective and practical, and that belief and desire are two distinct states. To embrace all these platitudes, we are forced to face the inconsistency among three stands: cognitivism, judgement internalism, and Humean theory of moral motivation. This is what Smith called “the moral problem” in the realm of metaethics. The central plank to solve the problem is to demarcate motivational reason and normative reason for action and then to provide an analysis of normative reason. Smith analyses normative reason in terms of the concept of fully rational agent. A fully rational agent is armed with the most coherent set of desire. Under the model of fully rational agent, the objectivity and practicality of morality are thus both maintained. However, a further investigation of the concept of coherence reveals that the model seems hardly to capture neither normativity nor practicality of morality. Smith may thus fail to solve the moral problem.