有別於經驗主義的途徑，本文試圖藉助自然主義的觀點，來探討 休謨「人性科學」的現代性意義。為此目標，作者將回到休謨的「理 性法庭」之中，從他所推許的「推理的實驗方法」與「懷疑主義的質 疑」，來反思理性與人性的爭鬥。雖然「人性科學」的研究範圍涵蓋 人類事務的所有領域，但為了集中討論，作者在此擬以因果推論作為 我們分析的主要例證。追隨休謨的研究腳步，我們終將發現，「推理 的實驗方法」與「懷疑主義的質疑」固然可以幫助我們揭露「理性的 造作」，但終究無法繼續毀滅「人性的堡壘」。換言之，休謨懷疑主義 的結論其實是積極的，其不但證成了日常生活習惯具有相對於理性與 哲學的自主性，並因而確認了經驗與情感在人類活動中的重要地位。

In contrast to the empiricist approach, this essay aims to explore the meaning of modernity in Hume’s “science of human nature” from a naturalistic point of view. To reach this goal, the author will go back to Hume’s “tribunal of human reason”, and consider how he reflects on the struggle between reason and human nature by means of the “experimental method of reasoning” and the “sceptical doubts”. Although the scope of the “science of human nature” covers almost every sphere of human affairs, in what follows the author only intends to take into account the issue of causal inference. Following Hume, we will find out that even though the “experimental method of reasoning” and the “sceptical doubts” can lead us to unveil the “pretensions of reason”, they would on longer be able to destroy the “castle of human nature”. The final result of Hume’s scepticism is, in fact, positive, in the sense that it justifies the customs of common life as an autonomous domain independent of reason and philosophy, and thus ensures the importance of experience and feeling in human action.