ジョン・ロックの認識論における観念と性質の類似について

Abstract

In An Essay concerning Human Understanding, Locke argues that, in the case of primary qualities such as size, shape or motion, ideas resemble the qualities they represent, while in the case of secondary qualities such as color, taste or sound, ideas are not like the qualities they represent. The puzzle is what exactly Locke means by "resemblance." Lockean ideas are mental entities, whereas qualities are physical properties. Given this metaphysical gap between ideas and qualities, it seems too naive to say that ideas may or may not resemble qualities literally. For this reason, many Locke scholars have interpreted "resemblance" in an anti-naive way. My aim in this paper is twofold : first, to argue that the naive interpretation is indeed the right interpretation of "resemblance"; secondly, to explain how Locke's epistemological method allows him to maintain that ideas may literally resemble qualities. We can vindicate the naive interpretation by dismissing the two leading antinaive interpretations : causal interpretation and intentional-object interpretation. The former is an interpretation, which avoids the above metaphysical problem by identifying the resemblance with the sameness of the vocabularies used for denoting ideas and qualities in the causal account of perception, as far as the primary qualities are concerned. Unfortunately, this interpretation begs the question because it presupposes the very point that an idea can have size, shape or motion as physical objects do. The latter interpretation is an attempt to dismiss the metaphysical problem by assimilating Lockean ideas with intentional objects, that is, the objects which appear to us. However, since Locke denies that ideas can be characterized as such objects, this interpretation must be rejected. Furthermore, Locke can avoid the metaphysical problem, while maintaining that the naive interpretation is plausible. Judging from the textual evidence, Lockean ideas should be understood as mental images. Now, the question is how these mental images can have properties such as size, shape or motion. We can find the answer to this question in Locke's epistemological method. In the metaphysical problem it is assumed that no mental entities, including ideas, can be extended, unlike physical properties. This idea can be dismissed in Locke's epistemology. His main epistemological device is a "historical, plain method, " a scientific method entirely based on our observations. This method implies that we must take an agnostic attitude towards the nature of mind because any inquiries into it go beyond our observations. This means that, in this method, the idea that no mental entities can be extended must be rejected as a dogmatic opinion. Thus, since Locke does not have to take the metaphysical problem seriously, there is no problem for him to maintain the resemblance between ideas and qualities in the naive way.