ABSTRACT
In the natural sciences, there has long been a continuous conceptual battle between the ‘‘lumpers’’ and the ‘‘splitters’’—those who wish to lump together phenomena with similarities as variations of an overriding mechanism and those who wish to split observed events into multiple independent phenomena with their own unique mechanisms. Nowhere is this lumper versus splitter dichotomy more apparent than in the field of pain research. Some would extrapolate all findings related to one type of painful stimulus to all types of painful stimuli in all sites. Others would claim that there can be no generalization of pathways or function for any pains arising from different parts of the body. Obviously, there is a middle ground where general principles may apply to many systems, but there may be mechanisms specific to individual systems. Such is the case with visceral pain.
