It is possible to empirically discriminate between the predictions of orthodox (i.e., Copenhagen) quantum theory and the de Broglie−Bohm theory of quantum mechanics. A practical experiment is proposed in which a single, laser-cooled ion inside an ultra-cold particle trap is either found to be near the trap’s walls or not. Detections of the former kind would support the prediction of orthodox quantum theory and of the latter kind would support the de Broglie−Bohm theory. The outcome of this experiment would show which theory gives the more correct description and, consequently, would have far-reaching implications for our understanding of quantum mechanics.