Triangulation and Rationality

In this paper, I want to argue against one of the several objections raised against externalist theories. According to this objection, externalism would actually lead to the irrationality of the subject. Even though this criticism has never been raised directly against Davidson’s kind of externalism, I think that it could be an interesting point to determine if triangulation is immune to it or not. Thus, I want to demonstrate that triangulation is unaffected by this objection either if we temporarily accept the notion of rationality implicit in the argument, or if, following Davidson’s intuitions, we reject it blocking the very criticism from the start. This article is divided into four sections. In the first one, I define the two concepts of rationality and rational agent involved in the argument against externalism. The analysis of these concepts leads to the fact that a subject, in order to be considered a rational subject, should be able to determine a priori if two thoughts have the same content or a different one. In the second part, I analyze the case in which a subject seems unable to realize whether two thoughts have the same content, while in the third one I will consider the opposite case in which a subject seems unable to distinguish two thoughts with a different content. At the end of each section, I try to demonstrate that Davidson’s theory of triangulation can answer both criticisms. Finally, in the fourth section, I try to show that the notion of rationality implied in the objection is itself profoundly flawed and then to propose a different account of rationality based on some of Davidson’s intuitions.