The changing conditions for the accumulation and transmission of knowledge in the age of multimedia networks make it inevitable that old philosophical problems become formulated in a new light. Above all, the problem of the unity of knowledge is once again a topical issue. The situation-dependent acquisition of knowledge that is made possible by mobile learning transcends the boundaries of traditional disciplines, linking the domains of text, diagram, and picture. Database integration and multimedia search become central problems in the epistemology (...) of the 21st century, while handheld devices are emerging as vital technologies for supporting collaborative learning. -- Kristóf Nyíri has published widely on Wittgenstein, Austrian intellectual history, and the philosophy of communication. He directs the interdisciplinary research program COMMUNICATIONS IN THE 21ST CENTURY, conducted jointly by the Institute for Philosophical Research of the Hungarian Academy of Sciences and Westel Mobile Telecommunications, Budapest. (shrink)