Bulletin of Symbolic Logic

Research Article

Heterogeneous Reasoning and Its Logic

Sun-Joo shin

Department of Philosophy, Yale University, New haven, Connecticut 06511, USA E-mail: Sun-Joo.Shin@yale.edu

Let me start by saying that I had the privilege of witnessing the birth of Jon Barwise's new research on heterogeneous logic and its subsequent developments. I entered the Stanford philosophy graduate program in the Fall of 1987, became Barwise and Etchemendy's first research assistant on the project of diagrammatic/heterogeneous reasoning during summer of 1989, and under their guidance completed my thesis, “Valid reasoning and visual representation,” in August, 1991. With this experience I would like to focus on the more personal and informal aspects of Jon's research on heterogeneous logic which may not be conveyed by his articles. (Accordingly, I have written this paper without footnotes or other references except to Jon's work.) The present article can only hint at the depth and the influence of Jon's work in this area.

In the first section, I single out an important feature of the project on heterogeneous logic Jon founded together with John Etchemendy about 15 years ago. I title it “resolving conflicts” since the research, I strongly believe, grew out of Jon's personal attitude toward how to resolve a tension between opposite extremes.

The second section focuses on how teaching logic itself was shaped as part of Barwise and Etchemendy's research agenda. It is worthwhile noting that their textbook Language, Proof, and Logic constitutes part of their research and, hence, the success of the book vindicates the goal of the overall project.

(Received December 12 2002)

(Revised February 22 2003)