Saving Unobservable Phenomena

In this paper I argue—against van Fraassen's constructiveempiricism—that the practice of saving phenomena is muchbroader than usually thought, and includes unobservable phenomenaas well as observable ones. My argument turns on the distinctionbetween data and phenomena: I discuss how unobservable phenomenamanifest themselves in data models and how theoretical modelsable to save them are chosen. I present a paradigmatic casestudy taken from the history of particle physics to illustratemy argument. The first aim of this paper is to draw attentionto the experimental practice of saving unobservable phenomena,which philosophers have overlooked for too long. The secondaim is to explore some far-reaching implications this practicemay have for the debate on scientific realism and constructiveempiricism.

1 Introduction

2 Unobservable Phenomena

2.1 Dataand phenomena

2.2 What isa data model?

2.3 Data modelsand unobservable phenomena

3 Saving Unobservable Phenomena:An Exemplar

4 The October Revolution of 1974: From the J/to Charmonium

4.1 A new unobservable phenomenon at 3.1 Ge V

4.2 How thecharmonium model saved the new unobservable phenomenon

4.2.1The J/ as a baryon–antibaryon bound state

4.2.2TheJ/ as the spin-1 meson of a model with three charmedquarks

4.2.3 The J/ as a charmonium state

5 Concluding Remarks