本文以分析亞理斯多德「無自制力」概念作為主題。亞理斯多德對此問題的討論基本上乃是由蘇格拉底之學說所引發的。根據柏拉圖在《普羅塔哥拉斯篇》的記載，蘇格拉底基本上認為，人們是不可能一方面「知道」何為「善」（對他有利之事），但另一方面卻違反這樣的認知而行為。亞理斯多德試圖駁斥這種說法，且試圖證明，無自制力的行為是可能的。本文將論述，這個對蘇格拉底學說的反駁，乃是亞理斯多德在《尼各馬科倫理學》第七書中基本立場以及主要企圖；他並非如同許多詮釋家所假定的那樣，是要去發展一套另一種版本的蘇格拉底學說。 由於亞理斯多德認為，無自制力者是該被責備的，因此，他從一開始便是在道德教養的脈絡下討論無自制力的問題。這個對無自制力的基本評價，構成了亞理斯多德對此問題整個討論的基本論題；許多對亞理斯多德無自制力學說的批判與誤解都是基於忽視了這個事實。誠然，如同許多學者假定的，亞理斯多德的無自制力學說不盡完備，因為無自制力這個現象可能恰好會破壞他原有倫理學的整個概念架構。然而，本文將證明，無自制力這個概念基本上仍然可以成功地被納入亞理斯多德的倫理學系統。最後，本文嘗試對「何以無自制力是該被責備的」這個問題，給予一個較為合理的解釋。

This paper is an analysis of Aristotle's concept of akrasia. Aristotle's discussion about this concept is motivated by the Socratic doctrine, elaborated in Plato's Protagoras, according to which it is impossible to know what good is and yet to act against this knowledge. Aristotle wants to rebut this doctrine and show that the akratic action is possible. I argue that this is his general concern in the 7. Book of Nicomachean Ethics, and that his doctrine of akrasia is not meant to be a mere restatement of the Socratic doctrine, as is usually supposed by commentators. Since Aristotle thinks that the akratic is balmeworthy, the problem of akrasia belongs in fact to his discussion about moral education. I argue that this general assessment of akrasia constitutes the fundamental issue of his discussion, and that many criticisms and misunderstandings about the Aristotelian doctrine have arisen from neglecting this very fact. Indeed, as generally supposed, Aristotle's doctrine of akrasia is still incomplete, since the possibility of this very phenomenon akrasia may undermine the whole conceptual framework of his ethical theory. However, this paper will show that it is possible to integrate the concept of akrasia into the Aristotelian ethics consistently. Finally, I attempt to give an explanation about why akrasia is blameworthy.