Contrary to Descartes' demand that modern science must aim for clear and distinct ideas, the fruitfulness of ambivalence and ambiguity, which was always recognized in art, is being given new attention, particularly in post-modernist thinking. The interdisciplinary theme of this volume is justified ambiguity or ambivalence. It is shown that limited unambiguity is also clearly conceivable. With contributions by Zygmunt Bauman, Friedrich Cramer, Hinderk M. Emrich, Reto Luzius Fetz, Fritz Hartmann, Kurt Hübner, Dietmar Kamper, Peter Koslowski, Knut Wolfgang Nörr, Richard Schenk, Rolf Schönberger and Falk Wagner.