I consider an underappreciated problem for proponents of the Humean theory of motivation (HTM). Namely, it is unclear whether is it to be understood as a largely psychological or largely metaphysical theory. I show that the psychological interpretation of HTM will need to be modified in order to be a tenable view and, as it will turn out, the modifications required render it virtually philosophically empty. I then argue that the largely metaphysical interpretation is the only a plausible interpretation of HTM's central claim that desires are necessary conditions for motivation. This interpretation also fits better with the important roles that HTM plays in both moral psychological and metaethical debates.

中文翻译：

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休谟动机理论是一种什么样的理论？

对于休谟动机理论 (HTM) 的支持者来说，我认为这是一个被低估的问题。也就是说，不清楚是将其理解为主要是心理学还是主要是形而上学的理论。我表明，HTM 的心理学解释需要修改才能成为一个站得住脚的观点，而且事实证明，所需的修改使其在哲学上几乎是空洞的。然后我认为，主要是形而上学的解释是对 HTM 的中心主张的唯一合理解释，即欲望是动机的必要条件。这种解释也更符合 HTM 在道德心理学和元伦理学辩论中所扮演的重要角色。