The potential of mobile communication for enhancing collaborative learning, and generally the changing nature of knowledge in the network age, make it inevitable that old philosophical problems become formulated in a new light. The problem of the unity of knowledge becomes once again a topical issue. Mobile learning situationdependent knowledge by its nature transcends disciplines. Its elements are linked to each other not just by texts, but also by diagrams, pictures, and maps. Many scientific activities today, too, are associated primarily not with printed texts, but with large multimedia databases. The problems of database integration and of multimedia search become central questions of the epistemology of the 21st century. This volume contains papers by, among others, Barry Smith, Donald Peterson, Mikko Ahonen, Graham Alsop, Andrea Kárpáti and Andy Stone.