title: Toward a new human pathology. I. Biopathological populations, or sets: a substitute for the old pathology's diseases.
abstract: Diseases are class concepts. They are used to group biomedical cases according to biopathological similarities perceived among them. Because calss concepts are mutually exclusive, a patient's ailment has to be considered as one, and only one, disease. However, as biotechnical data have multiplied, cross-over similarities among cases in different disease classes have become troublesomely frequent. For that reason, the abundance of data requires a method to handle overlap. Set theory differs from classification theory by allowing overlap among categories. Using set theory, a pathologist can assign a given case to as many biopathological sets as the data require. Therefore, biopathological set theory provides a substitute for mutually exclusive diseases, which are no longer a serviceable way to categorize cases and to organize the data of human pathology.
mesh_terms: D003933:Diagnosis; D004194:Disease / Q000145:classification*; D006801:Humans; D010336:Pathology