而在進一步討論理由與動機的關係之前，本文處理了幾個援引道德心理學所可能引發的理論爭議。最後，本文討論了規範性動機與規範性理由之間的幾種可能關係。自然主義法理學者Brian Leiter認為，僅具有規範性動機而無規範性理由；而哲學家Bernard Williams則認為規範性理由的必要條件之一就是行動者的動機。本文認為這兩種看待方式都有所偏頗，傾向以更為動態的方式理解兩者的關係。本文認為，規範性動機不能等同於規範性理由，但卻是人們尋找規範性理由的前提；就此而言，規範性動機與規範性理由的斷裂，其實顯示了規範性問題作為一縫隙問題，即所謂的規範縫隙（normative gap）。
Discussions about the normativity of law in Taiwan usually focus on H.L.A.Hart’s / Joseph Raz’s legal theories but fail to emphasize the theory of action. The initial objective of this thesis is to review two influential legal philosophers’ theories, in particular Joseph Raz’s action theory. Considering Raz’s action theory, I think that it cannot fully explain people’s normative actions and their underlying grounds and leaves remaining questions.
To answer these questions, we have to turn to the studies of the moral psychology. These studies show how people make moral judgments and take moral actions based on their moral intuitions. In a classic experiment on obedience, Milgram pointed out that people have less difficulty in obeying the authority intentionally than they imagined before accepting the experiment. Beginning from these psychological studies, this thesis then tackles the conditions shaping people’s obedience and demonstrates that the coherent intension of legal authority’s claim and the comprehensiveness of law are two important conditions altering people’s normative motivation. Before discussing the relationship between reasons and motivation, this thesis further deals with several theoretical disputes between moral psychology and normativity of law.
In the final chapter, this thesis presents and criticizes various theories concerning the relationship between normative reason and normative motivation. For instance, Brian Leiter, a naturalist legal philosopher, claims the non-exist of the normative reason and proposes that there are only normative motives. In contrast, Bernard Williams insists that the motivations are the necessary conditions constituting the normative reason. This thesis indicates that both approaches are biased and turn to depict the relationship between normative reason and normative motivation in a more dynamic way. Normative motives can’t be equated with normative reasons, but they serve as the prerequisite for people in search for normative reasons. In conclusion, the gap between normative motives and normative reason reveals the normative problem as a gap problem, or “normative gap”.