デイヴィッド・ヒュームにおける二つの原因 : 原因の定義問題に即して

Abstract

Undoubtedly, the causal theory proposed by Hume has been a representative one that still has great influence on philosophy today. However, there remain some distinct interpretations about how to understand his theory of causation. I think one of the reasons is that, although Hume explicitly gave a definition of cause in his Treatise and First Enquiry, he sometimes used the term "cause" in a meaning different from that expressed in the definition. Therefore, in order to grasp Hume's precise position on theory of causation, first of all, we need to carefully examine his ways of using "cause, " without restricting our consideration within his definition of cause. From the point above mentioned, this paper aims to distinguish Hume's conception of cause into two different parts, namely, the cause expressed in the definition and the cause introduced in a section in which Hume mentions "Rules by which to judge of causes and effects, " and to emphasize similarities and differences between those two "causes." Though the second cause has not thus far been much considered by commentators, I think we can't appreciate Hume's theory of causation without taking the second cause distinctly into account. First, I show that these two "causes" share the content of the three rules for causal inference and that the sharing, considered in itself, could lead us into "naïve regularity theory of causation" or merely an irrational and skeptical theory that many critics wrongly attribute to Hume. Second, I show that these two "causes" differ in faculty which operates when we conceive causes, and in how they can be justified in our causal inference. Besides imagination and custom, which are necessary for the first "cause, " the second "cause" requires reason and reflection. According to Hume, our causal inferences are essentially justified only by reflection. This seems to mean that we can justify only the second "cause, " but at the same time, I think, Hume implicitly suggests that the first "cause" too can be justified, in a different way from the second.