Cathy Legg

Integration of ontologies begins with establishing mappings between their concept entries. We map categories from the largest manually-built ontology, Cyc, onto Wikipedia articles describing corresponding concepts. Our method draws both on Wikipedia’s rich but chaotic hyperlink structure and Cyc’s carefully defined taxonomic and common-sense knowledge. On 9,333 manual alignments by one person, we achieve an F-measure of 90%; on 100 alignments by six human subjects the average agreement of the method with the subject is close to their agreement with each other. We cover 62.8% of Cyc categories relating to common-sense knowledge and discuss what further information might be added to Cyc given this substantial new alignment.

Much mainstream analytic epistemology is built around a sceptical treatment of modality which descends from Hume. The roots of this scepticism are argued to lie in Hume’s (nominalist) theory of perception, which is excavated, studied and compared with the very different (realist) theory of perception developed by Peirce. It is argued that Peirce’s theory not only enables a considerably more nuanced and effective epistemology, it also (unlike Hume’s theory) does justice to what happens when we appreciate a proof in mathematics.

This paper seeks an explanation for the challenges faced by Semantic Web developers in achieving their vision, compared to the staggering near-instantaneous success of the World Wide Web. To this end it contrasts two broad philosophical understandings of meaning and argues that the choice between them carries real consequences for how developers attempt to engineer the Semantic Web. The first is Rene Descartes’ ‘private’, static account of meaning (arguably dominant for the last 400 years in Western thought) which understands the meanings of signs as whatever their producers intend them to mean. The second is Charles Peirce’s still relatively unknown ‘public’, evolutionary account of meaning, according to which the meaning of signs just is the way they are interpreted and used to produce further signs. It is argued that only the latter approach can avoid the unmanageable attempts to ‘preprocess’ interpretation of signs on the Web which have dogged the project in its many stages, and thereby do justice to the scale, rapid changeability and exciting possibilities of online information today.