I thoroughly enjoyed the third biennial International UDC Consortium seminar at the National Library of the Netherlands, The Hague, last Monday and Tuesday. The UDC conference website includes the full programme and slides and the proceedings have been published by Ergon Verlag.
This is a first of a series of posts covering the conference.
Aida Slavic, UDC editor-in-chief, opened the conference by pointing out that classification is supposed to be an ordered place, but systems and study of it are difficult and complex. We still lack terminology to express and discuss our work clearly. There is now an obvious need to instruct computers to use and interpret classifications and perhaps our work to make our classifications machine readable will also help us explain what we do to other humans.
On being the same as
Professor Patrick Hayes of the Florida Institute for Machine Learning and Cognition delivered the keynote address, pointing out that something so simple as asserting that one thing is the same as another is actually incredibly difficult and one of the problems facing the development of the Semantic Web is that people are asserting that two things are the same when actually they are merely similar.
He explained that the formalisms and logic underpinning the Semantic Web are all slimmed down versions of modern 20th century logic based on a particular world view and set of assumptions. This works very well in theory, but once you start applying such logics to the real messy and complex world with real objects, processes, and ideas, the logics are put under increasing stress.
In logic, when two things are referred to as the same, this means they are two different names for the same thing, not that there are two things that are logically equivalent. So, Paris, the city of my dreams, and Paris the administrative area, Paris throughout history, and Paris – the capital of France are not necessarily all the same. This means that in logic we have to separate out into different versions aspects of an idea that in ordinary language we think of as the same thing.
He described this as the problem of “logic versus Occam” (as in Occam’s razor). Logic drives us to create complexity, in that we have to precisely define every aspect of a concept as a different entity. In order for the Semantic Web to work, we need to be very clear about our definitions so that we don’t muddle up different aspects of a concept.