Ranganathan’s universe of knowledge and categorial thinking Fulvio Mazzocchi CNR-Institute for Complex Systems (Italy) fulvio.mazzocchi@isc.cnr.it Introduction It has been argued that if any classification system or theory is to be fully understood it should be regarded as part of a specific socio-cultural and philosophical framework (Olson 2002; Hjørland 2003; Mazzocchi 2013). This implies that an inquiry into their foundations needs to include also an analysis of the underlying ontological and epistemological questions. Shiyali Ramamrita Ranganathan’s ideas about classification are not an exception. In this paper it is asserted that these ideas were influenced significantly by the Indian philosophical tradition, in which together with metaphysical thinking schools of logic and dialectics sprung up too. Some authors have stressed the kinship with the Nyaya- Vaisesika system (Adhikary and Nandi 2003). Indeed, Colon Classification embeds elements of the Hindu worldview, such as the idea of transitoriness in respect to the ceaseless transformation of the universe and above all the inclination to analyze existence in fundamental categories. The paper is structured as follows. First, I examine Ranganathan’s idea of the ‘universe of knowledge’. I highlight how his search for a new approach to classification (beyond the enumerative model) was instigated by this idea. Then Ranganathan’s approach is scrutinized in the light of the cultural background in which it developed. In particular, his PMEST is looked at against the background of the Indian philosophical tradition, comparing it with the Vaisesika categorial systems. Fìnally, the role of categorial systems as a cognitive means is analyzed. Certain basic categories have surfaced within the Indo-European linguistic and cultural frame in different ages and latitudes. The fact that they are somehow ‘culturally constructed’ does not undermine their role of establishing the meaningful domain of discourse of a cultural tradition. 1 Ranganathan’s universe of knowledge To investigate the nature of knowledge and its dynamics is of paramount importance for library science scholars and classification theorists, since the ‘world’ in which they are supposed to operate is made up of such items. Ranganathan’s ‘universe of knowledge’ is the universe of subjects (as an analogy of what occurs in chemistry, three types of subjects are distinguished: basic, compound and complex). This universe is described in terms of a complex, dynamic multidimensional space. It is a “dynamical continuum” which is “turbulently growing at every moment ” and made up of an “infinity of points” (Ranganathan 1951). Being a mathematician, a certain correlation between mathematics and classification theory is noticeable. For example, the idea of infinity with which Ranganathan describes the universe of subjects has been compared by analogy to the infinite set theory developed by the mathematician Georg Cantor in the late 19 th and early 20 th centuries (Hjørland 2013). The question is how to handle this dynamic complexity for practical purposes. Ranganathan was aware that we are living in an age typified by an increasing proliferation of subjects. New discoveries constantly occur and there is a social and intellectual interest for an advancement of research activity. He criticized the shortcomings of enumerative (classification) systems such as the Dewey Decimal Classification and Library of Congress Classification. These systems attempt to enumerate all possible subjects in a given domain within a fixed set of predetermined classes. However they encounter many problems in dealing with the dynamic aspect of knowledge. Their functional value would be greater if the ‘universe of knowledge’ corresponded to a closed system, but it is open and dynamic; new items are continuously added, resulting in the nonstop need for new classes to be created: “new branches may stem from any of its infinity of points at any time; they are unknowable at present. They cannot therefore be enumerated here and now; nor can they be anticipated, their filiations can be determined only after they appear” (Ranganathan 1951, 87ff.). In response to this, Ranganathan searched for a novel flexible approach based on a “sound resilient foundation” and capable of coping with continuous change in knowledge: