自由家父長主義主張，因其能保存當事人的選擇自由，故與自由主義不但不對立甚至相容。本文透過梳理Mill、Dworkin、Feinberg與自由家父長主義正當性論述的相關討論，指出兩者在人觀上存在根本性的差異：前者認為，人整體來說是理性及應被視為理性的，所以當事人的同意是家父長主義正當性的終極基礎；後者則透過行為科學的研究成果，指出人的系統性不理性，並據此論證家父長主義的必然性與正當性。但正是由於兩者相當不同的人觀預設，自由家父長主義，其對當事人選擇自由之保存的許諾，實質上很難存在，因此最終仍無法與自由主義相容。

Since its introduction, libertarian paternalism has significantly influenced political praxis, theory and public discourse. Proponents argue that it aligns with liberal democracies by enhancing individual well-being while preserving its freedom of choice. This article examines paternalism and libertarian paternalism, emphasizing a fundamental anthropological shift. Paternalism assumes individuals are fundamentally rational, with informed consent as its legitimacy cornerstone, even if they occasionally act irrationally. In contrast, libertarian paternalism, drawing from behavioral science, posits that humans are systematically irrational and shaped by external factors, necessitating and legitimizing paternalistic interventions.

I argue that libertarian paternalism, rooted in the assumption of human irrationality, fails to uphold genuine freedom of choice. Its proclaimed freedom remains nominal rather than substantive.