Wittgenstein's influence on the development of informal logic

Abstract

The perception exists that Wittgenstein was influential in the development of informal logic. That perception is probably based on several beliefs. One is the belief that Wittgenstein influenced some of those who are associated with the development of informal logic, like Toulmin. A second basis for the perception might stem from Wittgenstein’s association with what is sometimes called “ordinary language philosophy.” Informal logic emerged and has sometimes presented itself as “the logic of ordinary/everyday argument.” The purpose of this paper is to determine the degree to which the perception mentioned above is borne out by the facts. In the paper, I present the concept of informal logic that to be used in this paper, after which I make some comments about the task of interpreting Wittgenstein’s views and indicate the approach that I adopt. Next I discuss Wittgenstein’s influence on Toulmin, Hamblin, and Scriven–all of whose views about logic and argument have been important in the development of informal logic. I then turn to one direct application of his ideas, stemming from Fogelin’s 1985 paper “The Logic of Deep Disagreements.” The conclusion that I come to is that Wittgenstein’s influence on the development of informal logic has been indirect rather than direct, more a matter of “the spirit” behind informal logic than direct influence on any of its seminal thinkers.