Recent work in the field of middleware technology proposes semantic spaces as a tool for coping with the scalability, heterogeneity and dynamism issues arising in large scale distributed environments. Reflective middleware moreover offers answers to the needs for adaptivity and selfdetermination of systems where mobility and ubiquity add to such environments. Based on experiences with traditional middleware we argue that ontology-driven management is a major advancement for semantic spaces and provides the fundamental means for reflection. By means of ontologies, and ontology-based reasoning services we can implement automatic adaptation of the middleware?s functionality to environmental changes and user desires.