語言、思想與戴維森的三角測量隱喻

Language, Thought and Davidson's Triangulation Metaphor

思想和語言的關係為何？有些哲學家認為，語言在思想的構成上不扮演任何必要的角色；有些哲學家認為，語言只在某些思想，如意識性思想，的構成上扮演必要的角色。在〈Thought and Talk〉一文中，戴維森則論證一個看似極端的理論：所有思想的構成都涉及語言。更清楚地說，戴維森論證，只有詮釋者能是思想者，或，只有在人際間語言詮釋的脈絡下，思想才會產生。道個理論遭受了許多批評，部分原因是，這個主張蘊含一些頗為違反日常直覺和“科學發現＂的後果，例如，不具有語言能力的動物和人類的嬰孩，以及從未與他人進行語言溝通的人，原則上將不具有任何思想。然而，批評者對於戴維森如何論證這個理論卻一直不是很清楚。本文的目的是透過詳細研究戴維森在道個主題上的思想發展，來呈現出戴維森論證中所涉及之概念之內在關係，並且評估該論證之有效性。在本文中，我首先討論戴維森他早期的兩篇文章－－〈Thought and Talk〉和〈Rational Animals〉－－中所提出的論證：掌握信念的概念是具有思想的必要條件，而除非造行語言溝通，我們不能掌握信念的概念。由於戴維森所提供的論證只是建議性的，本文在此的首要工作著重在透過檢討他的論證的有效性來揭發他的論證走向。本文的後半部則是探討戴維森近年來如何透過三角測量隱喻去說明思想對語言的依憑性。三角測量隱喻在相當程度上補足戴維森早期論證的不足之處，雖然在某些要點上，三角測量隱喻所提供的論述仍是相當隱喻式的。三角測量隱喻在理解戴維森思想上是非常重要的，因為它不僅是戴維森對思想對語言的依憑性的主要論證，它也是他對思想和語言的公共性（社會性），以及三類知識（自我心靈知識，他人心靈知識，與世界知識）的相互依憑性，的主要論證。

Donald Davidson advocates the view that the constitutional involvement of language in thought is universal-- there cannot be any thought without language. More specifically, he argues that a creature cannot have thought, unless it is a member of a linguistic community, and an interpreter of the speech of others. The thesis invites many critics, mainly because it entails some seemingly counter-intuitive and counter-scientific consequences, like the idea that non-language-using creatures, such as animals and infants, and socially isolated people are not able to entertain any thought. In this paper, I however do not intent to join those critics, nor attempt a defense for Davidson from them. It is because that it has never been entirely clear in the first place how Davidson's argument works. The purpose of this paper is to provide a comprehensive picture and examination of Davidson's argument for the thesis that only a language interpreter can be a thinker. To achieve my goal, I first analyze in detail the relevant ideas and argument in his early works 'Thought and Talk' and 'Rational Animals'. In the two papers, Davidson argues that a creature cannot have a thought if it does not have the concept of belief, which no one can have unless he is a member of a speech community. Even though it is decided that the argument founded in the early two works is at best only suggestive, a full understanding of it nonetheless leads to a better understanding of Davidson's most mature argument for the dependence of thought on language, which is suggested in his triangulation metaphor. The triangulation metaphor manifests in a holistic way the internal connections among the concepts involved in Davidson's early argument, and so bridges some of the gaps appeared among them. The study of Davidson's triangulation metaphor by itself is interesting, for the metaphor offers ground not only for the accepting of the thesis at stake but also for Davidson's ideas that language and thought are public, and our knowledge of self, other minds, and the external world are interdependent.