Sustaining a Controversy: The Non-classical Ion Debate

This article examines a scientific controversy that raged for twenty years in physical organic chemistry during the second half of the twentieth century. After explaining what was at stake in the non-classical ion debate, I attempt—by examining the methodological reflections of some of the participants—a partial explanation of what sustained this controversy, particularly during its early stages. Instead of suggesting a breakdown of scientific method or the unavoidable historical contingency of scientific development, the endurance of this controversy instead reveals the heuristic and pragmatic character of many of the explanations and predictions generated by theoretical organic chemistry. The results in this case are used to suggest a new role for the study of scientific controversies in revealing the economics of scientific inquiry. 1 Introduction 2 The Non-classical Ion Debate 3 Models for the 2-Norbornyl System 4 Soft Theories and Reasoning by Analogy 5 Scientific Controversy and the Non-classical Ion Debate 6 Conclusion