<p>For decades, research on the Standard Model dominated the field of elementary particle physics and searches for new physics beyond it were driven by the predictions of particular models, among them supersymmetry. These predictions have not borne fruit at the Large Hadron Collider, and as such physicists are increasingly turning to experiment for guidance. In this paper, we provide a philosophical analysis of the change, diagnosing it as a shift in consensus on where the field of particle physics expects the most progress and by defining general criteria whether a field is driven by theory or experiment. We base our analysis of the history of particle physics on programmatic documents issued by the large experiments, summary reports at the annual conferences assembling nearly all particle physicists, and on expert interviews and questionnaires conducted by us over the past decade.</p>