This paper presents an account of how I developed the Dialogos approach to practical philosophy through action inquiry research. The process of development is understood as a contribution to the reconstruction of the notion "Bildung zur Humanität" as an ideal in education. Core perspectives, traditions and purposes involved in the action inquiry research process are outlined, discussed and divided into three phases: the humanistic-pedagogical phase, the ethical-philosophical phase, and the existential-spiritual phase. The Dialogos approach was later systematically tried out and evaluated through philosophical dialogues in empirical action research processes in the Gandhi Project and the Reconciliation Project.