道德責任能力、自由意志與神經科學－一個實用主義的觀察

在傳統論述上，當我們要求一個人對其行為負起道德責任時，我們認為這個人在行為時可以辨識是非，並依據其自由意志從事該行為。近來，受到神經科學理論的啟發，神經科學家與哲學家們開始反思自由意志與道德責任能力的關係。本文將責任之焦點集中在具有答責性之因果責任及能力責任上，從決定論、附帶現象論、自然主義、理性及情境主義等觀點，檢視自由意志之可能及其對道德責任能力之影響。以神經科學對於有意識的意志之探討為例，本文認為目前神經科學並不能解決自由意志存否之問題，然而，從一種結合神經科學與實用主義之觀點，強調寬廣的反思平衡，並以成癮行為之道德責任能力為例，筆者主張自由意志的社會意義仍無法化約成大腦活動之理解，以道德責任（能力）做為調和社會生活的重要制度，必須在個人心智活動層次肯認人類的某種自由為前提下，使之成為人類共同生活秩序維持的論述與行動之依歸。

關鍵字

自由意志；道德責任能力；神經科學；實用主義

並列摘要

Moral responsibility has been an important institution in the history of human sociocultural development. It requires a person to take responsibility for her past deeds so as to achieve retribution, change behavior, adjust interpersonal relationship and maintain social order. Traditionally, when we hold a person morally responsible for his act, we recognize the person is capable of distinguishing right from wrong and act according to his own free will. Recently, inspired by neuroscience, neuroscientists and philosophers began to deliberate the relationship between free will and moral responsibility. Focusing on causal responsibility and capacity responsibility in the framework of answerability and briefing criticisms on free will by determinism, epiphenomenalism, naturalism, rationality and situationism, this paper examines the question regarding the possibility of free will and how its answer might have impact on moral responsibility. Taking neuroscientific and philosophical debates on conscious will as an example, the paper argues that current neuroscience could not solve the problem of whether free will exists. Based on a combined perspective of neuroscience and pragmatism that adopts wide reflective equilibrium, the author concludes that the social meaning of free will could not be reduced to an understanding of brain activities. As an important institution mediating social lives, moral responsibility has to presume some form of human freedom, which is the Archimedean point of the discourses and actions maintaining the order for human beings to live together. Due to the sociocultural historicity of the free will discourse, neuroscience's exploration of the phenomenon and conception of free will tends to be dynamic and yet inspiring. However, it has limitation in resolving the problem of whether free will exists.