Levels of Reality and Levels of Representation
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Knowl. Org. 31(2004)No.3 151 C. Gnoli and R. Poli: Levels of Reality and Levels of Representation Levels of Reality and Levels of Representation Claudio Gnoli* and Roberto Poli** *University of Pavia. Mathematics Department Library, via Ferrata 1, I-27100 Pavia, E-mail: [email protected] **University of Trento and Mitteleuropa Foundation, E-mail: [email protected] Claudio Gnoli has been working as a librarian since 1994, and is currently at the Mathematics depart- ment of University of Pavia, Italy. His main interest is in theory of classification and its digital applica- tions. He is chair of the ISKO Italy chapter. Roberto Poli (1955) is Assistant Professor at the University of Trento (Italy). He obtained a Ph.D. in Philosophy from the University of Utrecht. Poli is editor-in-chief of Axiomathes (Springer), a peer- reviewed journal in ontology and cognitive systems, and co-founder of the Mitteleuropa Foundation (http://www.mitteleuropafoundation.it), a recently established research centre in ontology and cogni- tive analysis. Gnoli, Claudio and Roberto Poli. (2004). Levels of Reality and Levels of Representation. Knowledge Organization, 31(3). 151-160. 45 refs. ABSTRACT: Ontology, in its philosophical meaning, is the discipline investigating the structure of reality. Its findings can be relevant to knowledge organization, and models of knowledge can, in turn, offer relevant ontological suggestions. Several philosophers in time have pointed out that reality is structured into a series of integrative levels, like the physical, the biological, the mental, and the cul- tural, and that each level plays as a base for the emergence of more complex levels. More detailed theo- ries of levels have been developed by Nicolai Hartmann and James K. Feibleman, and these have been considered as a source for structuring principles in bibliographic classification by both the Classification Research Group (CRG) and Ingetraut Dahlberg. CRG’s analysis of levels and of their possible application to a new general classification scheme based on phenomena instead of disciplines, as it was formulated by Derek Austin in 1969, is examined in detail. Both benefits and open problems in applying integrative levels to bibliographic classification are pointed out. 1: Introduction between such levels and their possible representation in classification. As a traditional tool to organize The events and objects of our experience are classi- knowledge, bibliographic classifications are especially fied in many different ways: some forms of classifica- considered, and their relation with the theory of lev- tion depend on the way in which events and objects els is examined. are described, according to either our perceptions or The ontological approach is perhaps the most dis- our conceptualizations (e.g., in terms of salient fea- tant from the contemporary scientific perspective. tures); while other classifications depend on general For this reason, some brief words of clarification are patterns, or “universals”, wholly intrinsic to the advisable. It should first be noted that for some time events and objects of the world. We may call these the term and idea of “ontology” have begun to enjoy two opposite forms of classification epistemological currency in various sectors of artificial intelligence, and ontological. The purpose of this paper is to show and particularly in (1) representation of knowledge; that both ontological and epistemological analyses (2) theory of databases; (3) natural language process- unfold in degrees or levels, and to explore relations ing; and (4) automatic translation. In short, those 152 Knowl. Org. 31(2004)No.3 C. Gnoli and R. Poli: Levels of Reality and Levels of Representation who most frequently talk about ontology are re- the shopkeeper who displays the pen on his shelves searchers in the acquisition, integration, sharing and and seeks to sell it to customers, it is again different. re-utilization of knowledge. Ontology comes into To return to myself, the pen is also an object of play as a viable strategy with which, for example, to which I grew especially fond because it reminds me construct robust domain models. An ontologically of the person who gave it to me. grounded knowledge of the objects of the domain All these different descriptions are correct: each should make their codification simpler, more trans- of them expresses a facet of the object. Yet they are parent and more natural. Indeed, ontology can give all descriptions of the same object. Hence, one of the greater robustness to models by furnishing criteria main tasks of information science is to find ways to and categories by which to organize and construct integrate different descriptions of the same object. them; it is also able to provide contexts in which dif- Some of these descriptions have an ontological basis ferent models can be embedded and recategorized to (the pen has a given length, is made of a given mate- acquire greater reciprocal transparency (Poli, 1996; rial, etc.); others have an epistemological basis (to Poli & Mazzola, 2000; Poli, 2001a; Poli, 2002). Fur- my taste the pen is beautiful, I find it useful, etc.). thermore, it may be proved that ontological analyses ground epistemological analyses (Poli, 2001c). 3: Levels and creativity of reality 2: How much information is there? Ontologically, the example of the pen teaches us two important lessons: (1) reality is organized into strata Let’s consider the pen in front of me on my desk. (material, psychological, social); (2) these strata are What type of object is this pen? How should I model organized into layers (the physical and chemical lay- it? First of all, I may say that the pen is an object ers of the material stratum; the intentional and emo- made in a certain way, with its own shape, colour and tive layers of the psychological stratum; the produc- material. In saying this, I am using concepts that de- tive, commercial and legal layers of the social stra- scribe the physical world of things. The pen must tum). For every (type of) object, there must be a also perform functions: it has been designed to write. schema (or template) which coordinates and synthe- This reference to function introduces a different di- sizes the admissible descriptions of it; and for every mension into the analysis: writing, in fact, is not object, the template that best characterizes it must something that I can model using only concepts de- be elaborated. In the case of my pen, this might be scribing the physical world. Writing is an activity the template “artefact,” which implies the fact that typically performed by humans. By virtue of being the object is above all social in nature, and conse- constructed to fulfil the function of writing, the pen quently has social components (“is made by,” “for,” is in some way connected with this aspect of the “costs so much”). However, these dimensions do not world. But when I observe the pen, it tells me many account for the ontological structure in its entirety: other things. For example, that it has been con- most if not all of the artefacts also have a material structed by somebody, and that this somebody is my basis, and there may be also components embedded contemporary: this pen is not an object from the in its structure which evoke psychic components Roman age or from ancient China. The material (the affordances proposed by Gibson, 1979). An on- from which it is made, its manufacture, the way it tology must find a way of coordinating these aspects; works tell me that there must be somewhere an or- a wider description of the structure of an ontology is ganization producing things like pens. If we now provided by Poli (2001a; 2002). shift our focus to this organization, the pen must be Most researchers agree that our universe has a sin- an object designed, manufactured and distributed so gle common origin, often described as the “Big that it can be sold and end up on someone’s desk. In Bang.” The deep meaning of this thesis is that all the their turn, the points of view of the designer, of the varieties, diversities and structures of the universe are production department and of the distribution de- derived. Not only are flowers and universities de- partment are different, and they describe my pen us- rived objects, but so too are molecules, and atoms ing different concepts. For the designer the pen is es- and any particle thereof. All reality – better, all reali- sentially an aesthetic and functional object; for the ties – springs from that initial singularity. At this production department it is the outcome of materials point there are two possibilities: either the whole of processed in a certain way, etc. For the company reality is somehow, at least implicitly, stored in such a producing the pen it is all these things together. For singularity, or reality continuously grows and builds Knowl. Org. 31(2004)No.3 153 C. Gnoli and R. Poli: Levels of Reality and Levels of Representation new structures. Besides complexity issues, we simply guishing the specific categories of the material world cannot imagine any way in which the information from, for example, those of the psychological world, concerning the whole of reality can be compressed or from those of the social world. Each of these within a singularity. The only remaining option is to broad domains displays further categorical articula- accept the idea that reality is creative, and that new tions (e.g., the categories of physics are not those of realities constantly arise. If so, why should we con- chemistry, not those of biology, etc.). If the set-up fine our sense of reality to only a few of its struc- just described is at least partly plausible, a series of tures? The first structures to have emerged may be problems immediately arises.