One of the major challenges in the emerging interdisciplinary field of human-computer interaction (HCI) is the specification of a research line that can enable the development of validated design relevant knowledge with a predictive power for the design of interactive systems. Based on the three different elements in the design of interactive systems: (1) human being(s), (2) technical artifact(s), and (3) context of use, different disciplines contribute with different research paradigms to this new field: social sciences with a strong empirical and experimental approach, and engineering disciplines with a strong technical and formal approach. This paper presents and discusses a possible way to integrate the strengths of different research and design paradigms