Abstract
Every topic map has something in common with all other topic maps: a commitment to the goal of ” one topic per subject”, a state in which everything known about each distinct subject will be (apparently) co-located at its unique topic. A side effect of this commitment is that all topic maps, regardless of the diversity of the universes of discourse in which they are expressed, inherently facilitate their combination with other topic maps. Thus, all topic maps, in all universes of discourse, can be accurately regarded as contributions to the ability of diverse human communities to understand each other. Even though they may use diverse – and even logically incompatible – universes of discourse, all topic mappers are themselves members of a community whose unifying conviction is that subjects exist apart from, and are more important than, any particular ways of identifying them and co-locating information about them.
