A discussion of the papers, "Representation, Vision and Visualization: Cognitive Functions in Mathematical Thinking. Basic Issues for Learning" (Raymond Duval) and "On the Development of Human Representational Competence from an Evolutionary Point of View: From Episodic to Virtual Culture" (James J. Kaput), is presented. Kaput points to the accelerating emergence of increasingly virtual worlds with which and through which humans interact. Duval emphasizes that thoughtful, didactic attention must be given to helping students employ any register of representation powerfully and flexibly, and that deep mathematics emerges from coordinating specific register-centered activities. This paper suggests that it would be interesting for Duval to analyze Kaput's virtual worlds in terms of registers of representations and didactical strategies, and for Kaput to analyze Duval's didactics in terms of virtual culture. (Contains 10 references.) (DDR)