What is This Science Called Requirements Engineering?

This vision paper reflects on the nature and status of requirements engineering as a science, based on recent RE journal articles on methodological foundations and research classification such as (R. Wieringa, et al., 2006). We put this discussion into the wider perspective of ongoing debates in other areas, including social and natural sciences methodology, IS and design research. We propose a new categorization of the notions of validity and evaluation, and suggest a criterial framework inspired by work on the structure of scientific argument