“The best science comes to a great extent from the invention of new classifications of natural phenomena, the ones that suggest hypotheses and new rounds of data gathering.” Robert MacArthurAs quoted in Edward O. Wilson, The Naturalist [1] As painstaking scientific work gradually penetrates the diagnostic uncertainty and pathophysiologic mystery obscuring the nature of complex regional pain syndrome (CRPS), so will it raise the hopes of our patients suffering this dread disease. Progress in medical science usually comes not in a blinding flash of brilliance but rather in the gradual illumination of a disease through the dedicated scientific process of a team, and more often several teams, systematically and doggedly pursuing information about an idea and what the analysis of this information reveals. In this fertile soil of endeavor, understandings will grow, often by spurts of intuitive brilliance based on the intensity and longevity of the tilling. So it is with RSD and causalgia, now CRPS 1 and 2. Hardin and colleagues in this issue of Pain Medicine take us several steps ahead on this scientific quest in their report on the results of a consensus conference, held in Budapest, Hungary [2]. The value of their work to the field and the public cannot be overstated. Utilizing “Dahlem” think tank methodology, the conference systematically reviewed the extant literature and analyzed the validity of IASP criteria for CRPS. Their contribution is obtaining a sensible balance—between the clinician's need for sensitivity to avoid missing cases and the investigator's need for specificity to avoid over-diagnosis. Scientists need specificity, strict criteria to reduce sampling errors (non-cases designated as cases) that could confound the results of an expensive clinical trial and lead further investigations astray. Clinicians need sensitivity, more relaxed boundaries to avoid the clinical sin of missing cases that might benefit from …