Heidegger's Grundstimmungen (fundamental tonalities) and philosophical thought

The conception of philosophy which emerges from Heidegger's texts in the pe riod 1925-1930 is characterized in particular by the major role it gives to "fundamental tonalities" (Grundstimmungen). These are then interpreted as sentiments which concern certain men in their singularity. Later Heidegger was to propose more and more systematically a historical conception of thes e same tonalities, while not substantially modifying the interpretation of the act of philosophising which they control. However, it seems impossible to thing philosophising as does, for example, the course of the winter of 1 929-1930, in regard to Grundstimmungen that have become "historical".