Nursing is often described from the point of view of either the natural or the human sciences. In contrast to this, the value foundation in Interactional nursing practice is understood from the point of view of the natural sciences as well as that of the human and social sciences. This article presents many-faceted practice-theory of nursing, which is situated in the dynamic field between these three sciences. The focus of the theory is on interaction and practice resulting in a caring practice. Here practice is based on Taylor's and MacIntyre's interpretation of this concept. Action in nursing is based on Habermas' three varied modes of action seen in the light of an understanding of the world as a system world and a life world. Nursing as an interactional practice-theory is presented with examples of interpretative nursing science, seen in the ethical action-oriented, socio-cultural framework of Taylor and Habermas. It is concluded that phenomenologic and socio-cultural research into caring practice as well as an in-depth, comprehensive interpretation of nursing practice are both highly suited to forming the fundamental theoretical framework in nursing, here seen as an interpretative nursing science. Finally, a comparison is drawn between Interactional nursing practice and Benner's theory of nursing practice.