The "existential" stage is often traced back to Martin Heidegger's Being and Time.  
The "realistic" tendency stresses the search for the universal essences of different sorts of matters.  The first manifestation of the "hermeneutical" type is represented by Hans-Georg Gadamer.  The "constitutive" variety is most devoted to reflections on a namesake method.  The "existential" stage is often traced back to Martin Heidegger's Being and Time.  For 10 points, what school of philosophy was based on the work of Edmund Husserl?
The "realistic" tendency stresses the search for the universal essences of different sorts of matters.  
{phenomenology}