实践知识概念在当代行动哲学中由安斯康姆首次提出。实践知识是施动者关于其意向行动的知识。安斯康姆的实践知识概念的要点在于它的实践性，即导致意向行动。在这个意义上，实践知识区别于思辨知识。安斯康姆并且认为，施动者在行动失败时仍有实践知识。安斯康姆对失败行动的理解引起了广泛的争议，因为这似乎与知识的事实性相冲突。本文通过论证安斯康姆实践知识的非观察性来讨论其实践性，其核心任务是回应行动失败问题。本文将从行动的持续性、能力之知对于实践知识的必要性、道德知识的驱动性以及实践推理的结论这四个方面论证实践知识的实践性，力图对所探讨的问题给出尝试性解决。

    本文第一章讨论安斯康姆的实践知识概念。恰当地理解实践知识是意向行动的原因，这是解决行动失败问题的出发点。本章支持实践知识是意向行动的形式因。也就是说，实践知识构成性地导致意向行动。实践知识在逻辑上先于意向行动，但并不在时间上先于意向行动。本章并从以下两个角度解决行动失败问题。第一，意向行动是一个持续进行的过程而非已完成的事件。当行动发生中断或失败时，这并不意味着行动的结束，这个行动对于更广义的行动来说，还是一个正在继续的过程。因此，行动还不算失败。第二，知觉在意向行动中具有辅助作用。实践知识虽然不要求对行动的观察，但要求对环境的观察。在意向行动的实施中，施动者观察外部世界并确认自己的实力。

    本文第二章讨论能力之知的实践性何以支持实践知识的实践性。行动失败案例表明能力之知对实践知识的重要性。本章支持塞提亚的能力之知必要论，坚持能力之知是实践知识的必要条件，从而以能力之知的实践性支持实践知识的实践性。本章并从以下两个角度阐述能力之知在实践知识中的作用：第一，能力之知与意图存在规范联系。第二，能力之知是意向行动的核心。此外，塞提亚的能力之知必要论并不否认实践知识的实践性与能力之知的实践性存在区别。也就是说，实践知识的实践性在于描述行动，能力之知的实践性在于确保成功。实践知识不是能力之知，因而不受行动结果的约束，但实践知识往往要求某种能力之知。

    论文第三章讨论一种特殊形式的实践知识，即道德知识。本章通过讨论道德知识的实践性与能力之知的实践性的区别来体现实践知识的实践性区别于能力之知的实践性。特别地，本章将重点讨论美德与技能的区别。第一，美德与技能所具有的共同特征不足以说明美德是一种技能。第二，美德的强技能模型具有不可克服的困难，它不能说明美德的动机特征。第三，美德的弱技能模型不能成功地将美德与技能相类比，而且它也不能成功回避强技能模型所面临的困难，即它也无法说明美德的动机特征。第四，美德体现为一种特殊形式的实践知识，而非一种特殊形式的技能。与道德知识密切相关的美德并非特殊的技能，这样实践知识的实践性不同于能力之知的实践性，从而解决行动失败问题。

    本文第四章通过考察实践推理的结论，阐明实践知识的实践性，从而彻底解决行动失败问题。本文支持行动论，即认为实践推理的结论是行动。行动论可以辩护实践知识的非观察性。实践判断、实践推理与实践知识存在以下联系：一个实践判断是否算作实践知识不是由它所导致的意向行动决定的。恰恰相反，一个实践判断导致什么样的行动取决于它是否是实践知识。实践判断是否是实践知识，取决于相关的实践推理的有效性。而实践推理的有效性取决于其小前提是否具有关于当下情境及其自身实力的思辨知识。因此行动论可以成功地解决行动失败问题。

    The concept of practical knowledge was first introduced in contemporary philosophy of action by G.E.M. Anscombe. Practical knowledge is the knowledge of the agent about his or her intentional action. The main point of Anscombe’s concept of practical knowledge is that it is practical in the sense that it leads to intentional action. In this sense, practical knowledge is distinguished from speculative knowledge. Anscombe also argues that the agent still has practical knowledge when the action fails. Anscombe’s understanding of failed action is widely disputed because it seems to conflict with the factual nature of knowledge. This paper discusses the practical nature of Anscombe’s practical knowledge by arguing for its non-observational nature, with the central task of responding to the problem of action failure. The paper will argue for the practicality of practical knowledge in terms of the continuity of action, the necessity of knowing-how for practical knowledge, the driving nature of moral knowledge, and the conclusions of practical reasoning, in an attempt to give an attempted solution to the problem explored.

    The first chapter of this paper discusses Anscombe’s concept of practical knowledge. A proper understanding of practical knowledge as the cause of intentional action is the starting point for solving the problem of failed action. The chapter supports the idea that practical knowledge is a formal cause of intentional action. That is, practical knowledge constitutively causes intentional action. Practical knowledge logically precedes intentional action, but not temporally. This chapter further addresses the problem of failed action from two perspectives. First, intentional action is an ongoing process rather than a completed event. When an action is interrupted or fails, this does not mean that the action is over; the action is still a continuing process for the broader action. Therefore, the action is not yet a failure. Second, perception has a supporting role in intentional action. While practical knowledge does not require observation of the action, it does require observation of the environment. In the performance of intentional action, the agent observes the external world and confirms his strength.

    The second chapter of this paper discusses how the practical nature of knowing how supports the practical nature of practical knowledge. The case of action failure shows the importance of knowing how for practical knowledge. This chapter supports Setiya’s Necessity Thesis of Knowing-How by insisting that knowing how is a necessary condition for practical knowledge, so that the practicality of knowing how supports the practicality of practical knowledge. This chapter also elaborates the role of knowing how in practical knowledge from the following two perspectives: first, knowing how is normatively linked to intention. Second, knowing how is core to intentional action. Moreover, Setiya’s Necessity Thesis of Knowing-How does not deny there is a difference between the practicality of practical knowledge and the practicality of knowing-how. That is, the practicality of practical knowledge is in describing action, and the practicality of knowing how is in ensuring success. Practical knowledge is not knowing how, and thus is not bound by the results of action, but practical knowledge often requires some kind of knowing how.

    The third chapter of this paper discusses a particular form of practical knowledge, namely moral knowledge. This chapter exemplifies the practical nature of practical knowledge as distinct from the practical nature of knowing how by discussing the difference between the practicality of moral knowledge and the practicality of knowing how. In particular, this chapter will focus on the distinction between virtue and skill. First, the common features shared by virtues and skills are not sufficient to show that virtue is a kind of skill. Second, the Strong-Skill Model of virtue has insurmountable difficulties; it cannot account for the motivational features of virtue. Third, the Weak-Skill Model of virtue does not succeed in analogizing virtue with skill, and it does not succeed in avoiding the difficulties faced by the Strong-Skill Model, i.e., it also fails to account for the motivational character of virtue. Fourth, virtues are embodied in a particular form of practical knowledge rather than a particular form of skill. Virtues, which are closely related to moral knowledge, are not special skills, so that the practical nature of practical knowledge is different from the practical nature of knowing how. Thus, solving the problem of failed action.

    The fourth chapter of this paper addresses the problem of failed action once and for all by examining the conclusions of practical reasoning and elucidating the practical nature of practical knowledge. The paper supports the Action View, which holds that the conclusion of practical reasoning is action. The Action View can defend the non-observational nature of practical knowledge. Practical judgment, practical reasoning, and practical knowledge are related in the following way: whether a practical judgment counts as practical knowledge is not determined by the intentional action it leads to. Rather, the kind of action a practical judgment leads to depends on whether it is practical knowledge. Whether a practical judgment is practical knowledge depends on the validity of the associated practical reasoning. And the validity of practical reasoning depends on whether its minor premise has speculative knowledge about the present situation and its strengths. Thus, the Action View can successfully address the problem of action failure.