In this paper we have argued for a new conceptualisation of strategic foresight. The existing approaches are largely based on too simple a concept of future. It is usually assumed that one is able to conceptualise already in the present all possible future developments. We contrast this with the concept of a 'radically open' future, which might develop in ways which go beyond of what our cognitive categories allow us to conceptualise. Drawing on linguistic philosophy it is shown how our thinking and communicating is limited by our linguistic categories. Strategic foresight from this perspective is largely concerned with the adjustment of the linguistic system to novel developments of the world. This requires openness towards new linguistic categories. Drawing on the philosophical concepts of 'anticipating critique' by Paul Feyerabend and 'occasional reason' by Helmut Spinner we try to show how such openness can be accomplished.