One of the main reasons for philosophers to have embraced Humean constructivism rather than Kantian constructivism is a negative one: they believe that in the end Kantian constructivism is an unstable position. Their idea is that the Kantian constructivist can either choose to hold on to the idea of categorical reasons for action but in that case she has to be prepared to commit to (robust) moral realism (which both Humean and Kantian constructivists reject) or alternatively, she might reject (robust) moral realism but in that case she has to give up on the idea of categoricity. The aim of this paper is to defend Kantian constructivism against Humean constructivism and more specifically against recent objections raised by Sharon Street. I will do so by arguing that Kantian constructivism follows from formal, normative commitments that pertain to instrumental reasoning that Humean constructivists like Sharon Street themselves accept. More specifically I will argue that categorical reasons for action follow from applying the principle of instrumental rationality to the first-person perspective of an agent, provided that there are certain necessary means for action in general. From this follows, I will argue, that Humean constructivists should either become Kantian constructivists or that they have to become sceptics about normativity.

中文翻译：

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为什么Humean建构主义者应该成为康德建构主义者

哲学家之所以接受Humean建构主义而不是Kantian建构主义的主要原因之一是负面的：他们最终认为Kantian建构主义是一个不稳定的立场。他们的想法是，康德的建构主义者可以选择坚持采取行动的绝对理由这一观点，但在这种情况下，她必须准备坚守（健壮的）道德现实主义（悍然和康德的建构主义者都拒绝）。她可能会拒绝（健壮的）道德现实主义，但在那种情况下，她不得不放弃归类的想法。本文的目的是捍卫康德的建构主义反对休曼主义的建构主义，尤其是反对沙龙街最近提出的反对意见。我将通过论证康德建构主义是从形式，与工具推理相关的规范性承诺，如沙龙街（Sharon Street）这样的Humean建构主义者自己接受。更具体地说，我将辩称采取行动的绝对原因是将工具理性原则运用于代理人的第一人称视角，前提是总的来说有某些必要的行动手段。因此，我认为，休曼建构主义者应该成为康德建构主义者，或者必须对规范性持怀疑态度。前提是总体上有某些必要的行动手段。因此，我认为，休曼建构主义者应该成为康德建构主义者，或者必须对规范性持怀疑态度。前提是总体上有某些必要的行动手段。因此，我认为，休曼建构主义者应该成为康德建构主义者，或者必须对规范性持怀疑态度。