Ranganathan’s principles and a fully “freely faceted” classification

Among Ranganathan’s outstanding contributions to library and information science are the principles of faceted classification. He implemented them in his Colon Classification (CC), an advanced system bringing many innovations though still based on disciplines. The Integrative Levels Classification (ILC) breaks the barriers between disciplines and follows the alternative approach, phenomenon-based classification, which Ranganathan considered to be unsuitable. To express the facets of phenomena, ILC adopts a set of ten fundamental categories – quality, quantity, part, property, transformation, opposition, agent, place, time, perspective – that have some correspondences with Ranganathan’s PMEST. It is a “freely faceted classification” in the sense that any phenomenon class can be used as an isolate and combined with any other by means of free facets: these are not available in CC, although similar functionalities are provided by phase relationships and by subject device. ILC notation also adopts some solutions inspired by Ranganathan, such as emptying digit (z) and favoured host class (T). Expressive notation as in CC and ILC is especially useful, although underused, to control browsing and searching in our era of computer-based information.