Saving unobservable phenomena

Abstract

In this paper I argue - against van Fraassen's constructive empiricism - that the practice of saving phenomena is much broader than usually thought, and includes unobservable phenomena as well as observable ones. My argument turns on the distinction between data and phenomena: I discuss how unobservable phenomena manifest themselves in data models and how theoretical models able to save them are chosen. I present a paradigmatic case study taken from the history of particle physics to illustrate my argument. The first aim of this paper is to draw attention to the experimental practice of saving unobservable phenomena, which philosophers have overlooked for too long. The second aim is to explore some far-reaching implications this practice may have for the debate on scientific realism and constructive empiricism. 1 Introduction 2 Unobservable Phenomena 2.1 Data and phenomena 2.2 What is a data model? 2.3 Data models and unobservable phenomena 3 Saving Unobservable Phenomena: An Exemplar 4 The October Revolution of 1974: From the J/ψ to Charmonium 4.1 A new unobservable phenomenon at 3.1 GeV 4.2 How the charmonium model saved the new unobservable phenomenon 4.2.1 The J/ψ as a baryon-antibaryon bound state 4.2.2 The J/ψ as the spin-1 meson of a model with three charmed quarks 4.2.3 The J/ψ as a charmonium state 5 Concluding Remarks. © The Author (2007). Published by Oxford University Press on behalf of British Society for the Philosophy of Science. All rights reserved.