Permalink : http://hdl.handle.net/2115/68204

JaLCDOI : 10.14943/ouyourin.10.17

Chapter 12 in the book, Reasons and Persons (1984), written by Derek Parfit, has a well-known content on thought experiments based on “split–brain” researches. In this study, we aimed to interpret chapter 12 based on the “neuroscience of ethics” point of view in neuroethics. Moreover, we also considered the ideas of Sperry and Gazzaniga, who were the leaders of “split-brain” researches and the growth of cognitive neuroscience because of their influence in solving the issue as to why Parfit was interested in neuroscience. Parfit’s thought experiments lacked reality, and his comprehension of“ split–brain” researches was unsuitable because he believed that the real brain structure and mechanism were not so important. Furthermore, his research was evidently limited to the field of authentic ethics and not as a pioneer of a new field such as neuroethics. However, he still greatly contributed in establishing neuroethics. In the book, Reasons and Persons (1984), he unconsciously reported the relationship between the real brain structure and mechanism and the ethical issues before the dawn of neuroethics. Consequently, he told the researchers interested in the real brain structure and mechanism that ethical issues were just next door to them. Therefore, he played a role in the whistle for starting neuroethics.
Parfitの「理由と人格」（1984）において分離脳研究の思考実験で著名な第12章を中心に、Parfitとその後に発展した脳神経倫理学、特に倫理の神経科学（neuroscience of ethics）との関係を検討した。また、分離脳研究を発展させたSperryとGazzanigaを中心に認知神経科学の発展の歴史を振り返ることで、Parfit が神経科学に注目した理由を探った。しかし彼の理論にとって脳の実際の物理的構造はほとんど重要性を持たないため、思考実験自体にリアリティーが欠け、分離脳研究の解釈にも問題点が見られた。また、自らはオーソドックスな倫理学のフィールドから足を踏み出すことがなく、脳神経倫理学という新たなフィールドを開拓しなかったことは、Parfitの限界といえる。それでも、脳神経倫理学の夜明け前に脳の構造と倫理学的課題を（無自覚的ではあっても）結びつけ、結果的に脳の構造に関心を抱く人々に倫理学的課題がごく身近にあることを理解させた彼の功績は、脳神経倫理学の嚆矢と呼ぶべきである。