Abstract

The paper deals with how societies of the past have dealt with their future. It proposes a new approach, called anticipatory knowledge , focusing on how forecasting techniques have been articulated to organising activities in various contexts - highlighting the limits of classical approaches in terms of history of the future (Hölscher) or regimes of historicity (Hartog). The approach is introduced on the case of water-supply projects, on the notion of water needs , a calculation tool used from the middle of the 18th century in water-supply projects. Comparing four different projects for Paris, between the 1760s and the 1890s, the paper shows how conceptions of the future have gradually evolved, from static to more dynamic conceptions, relating the future to objects in the present, to trends in the past, to various attitudes towards growth.