法律、道德與自然必然性：論哈特的自然法最低限度內容

法律與道德無必然關連的分離命題，主要涵蓋內容、效力及證立分離三項命題。法實證論者大多支持前兩個命題，對證立分離命題卻有分歧看法。哈特主張法律與法體系的存在不必然要有某種道德證立觀點，拉茲和麥考密克則認為必然得訴諸道德證立，而富勒、德沃金、芬尼斯等非法實證論者皆以「厚實」道德觀點批評這三個分離命題。然而，這些論者卻鮮少對哈特辯護證立分離命題的重要論點，即「自然法的最低限度內容」進行深入檢視和批判。是以，本文嘗試審視和反思這個論點，首先指出自然法最低限度內容蘊含「自然事實論證」與「道德可謬性論證」（二），接著批評這兩個論證難以有力支持證立分離命題（三、四），最後是結論（五）。

關鍵字

法律；道德；自然法最低限度內容；自然必然性；實證道德；批判道德

並列摘要

The positivist separation thesis that there is no necessary connection between law and morality consists of three sub-theses: they are the separations of content, validity, and justification. Contemporary legal positivists usually defend the first two but have divergent opinions on the third. Hart insists that the existence of law and legal systems does not necessarily depend on moral justification, whereas MacCormick and Raz endorse the opposite view. Likewise, non-positivists all repudiate these sub-theses from a ＂thick＂ moral viewpoint of law. Nevertheless, critics rarely pay attention to Hart's most important argument in defending the justification separation thesis. It is the argument of the minimum content of natural law. I argue that Hart's account is based on the natural fact argument and the moral fallibility argument. The first is not, as he defends it, a descriptive statement, but a prescriptive one. It also violates ＂the naturalistic fallacy＂ he uses to criticize classical natural law doctrine. The second is not a morally neutral argument to describe the existence of an evil legal system. I shall argue that the minimum content of natural law is premised on the moral justification of ＂natural necessity＂.