The notion of ‘discourse’, as developed in some contemporary approaches to political analysis, has its distant roots in what can be called the transcendental turn in modern philosophy – i.e. a type of analysis primarily addressed not to facts but to their conditions of possibility. The basic hypothesis of a discursive approach is that the very possibility of perception, thought and action depends on the structuration of a certain meaningful field which pre-exists any factual immediacy. A transcendental enquiry as an investigation of the conditions of possibility of experience started with Kant, for whom space, time and the categories of understanding constitute the a priori dimension in the constitution of phenomena. And in the early twentieth century Husserl’s phenomenology strictly differentiated an intuition of facts from an intuition of essences, and asserted that the latter is constitutive of all ‘givenness’. These classical transcendental approaches differ, however, in two crucial respects from contemporary theories of discourse. The first is that, while in a philosophy like Kant’s the a priori constitutes a basic structure of the mind which transcends all historical variations, contemporary discourse theories are eminently historical and try to study discursive fields which experience temporal variations in spite of their transcendental role – i.e. that the line separating the ‘empirical’ and the ‘transcendental’ is an impure one, submitted to continuous displacements. A second differentiating feature is that the concept of ‘discursive fields’ in contemporary approaches depends on a notion of structure which has received the full impact of Saussurean and post-Saussurean linguistics.