Knowledge evolves in a cycle of knowledge liquidization and crystallization. The
evolving process takes place through the interactions among conceptual worlds,
representational worlds, and the real world (Figure 1). In the real world, real objects
(including humans) exist and certain relations hold among them. In a representational
world, there exist words and texts in natural languages and other forms of representations including diagrams, graphs and pictures. A conceptual world exists in
the human mind and concepts are formulated there.