klassifikations

Klassifikation, or classification, is the process of organizing items into groups or categories based on shared properties or criteria. It is used to reduce complexity, enable retrieval, and support reasoning across many fields. Classifications can be descriptive—grouping items by observed features—or prescriptive, establishing rules for how items should be organized. They may be formal and hierarchical, forming taxonomies with multiple levels, or flat, with a single layer of categories. In practice, classifications are structured by criteria, which may be concrete (shape, size) or abstract (function, domain).

Common forms include taxonomies, ontologies, and thesauri. Overlaps and ambiguities are common, and some systems use probabilistic or fuzzy membership to express partial belonging. Applications are widespread. In biology, the Linnaean taxonomy groups organisms into kingdoms, phyla, classes, orders, families, genera, and species. In information management, data classification assigns labels to documents or data sets for access control and retrieval; in machine learning, supervised classification assigns class labels to instances based on training data. Libraries and archives use classification schemes such as Dewey Decimal or Universal Decimal Classification to organize holdings. Medicine uses coding systems like ICD to classify diseases and procedures.

Challenges include keeping classifications up to date with new knowledge, addressing cultural biases, and balancing granularity with usability. The study of classification intersects with information science, philosophy, cognitive science, and data governance.