In this paper I revisit Gregory Kavka’s Toxin Puzzle and propose a novel solution to it. Like some previous accounts, mine postulates a tight link between intentions and reasons but, unlike them, in my account these are motivating rather than normative reasons, i.e. reasons that explain (rather than justify) the intended action. I argue that sensitivity to the absence of possible motivational explanations for the intended action is constitutive of deliberation-based intentions. Since ordinary rational agents display this sensitivity, when placed in the toxin scenario they will believe that there is no motivational explanation for actually drinking the toxin and this is why they can’t form the intention to drink it in the first place. I thus argue that my Motivating-Explanatory Reason Principle correctly explains the toxin puzzle, thereby revealing itself as a genuine metaphysical constraint on intentions. I also explore at length the implications of my account for the nature of intention and rational agency.

中文翻译：

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那么，为什么不打算喝毒素呢？

在本文中，我将重温格雷戈里·卡夫卡（Gregory Kavka）的《毒素之谜》，并提出一种新颖的解决方案。像以前的某些论述一样，我的假设也将意图和原因紧密联系在一起，但与它们不同的是，在我看来，这些动机是动机而非规范性原因，即解释（而非证明）预期行动的原因。我认为，对预期的行为缺乏可能的动机解释的敏感性是基于审议的意图的构成。由于普通的理性行为者表现出这种敏感性，因此将其置于毒素的情况下，他们会认为没有饮用真正动机的动机解释，这就是为什么他们不能一开始就饮用这种毒素的意图。因此，我认为我的动机解释性原因原理正确地解释了毒素之谜，从而表明自己是对意图的真正形而上学约束。我还将详细探讨我的论述对意图和理性代理性质的影响。