ABSTRACT
The positivity of a discourse — like that of Natural History, political economy, or clinical medicine — characterizes its unity throughout time, and well beyond individual œuvres, books, and texts. This unity certainly does not enable us to say of Linnaeus or Buffon, Quesnay or Turgot, Broussais or Bichat, who told the truth, who reasoned with rigour, who most conformed to his own postulates; nor does it enable us to say which of these œuvres was closest to a primary, or ultimate, destination, which would formulate most radically the general project of a science. But what it does reveal is the extent to which Buffon and Linnaeus (or Turgot and Quesnay, Broussais and Bichat) were talking about ‘the same thing’, by placing themselves at ‘the same level’ or at ‘the same distance’, by deploying ‘the same conceptual field’, by opposing one another on ‘the same field of battle’; and it reveals, on the other hand, why one cannot say that Darwin is talking about the same thing as Diderot, that Laennec continues the work of Van Swieten, or that Jevons answers the Physiocrats. It defines a limited space of communication. A relatively small space, since it is far from possessing the breadth of a science with all its historical development, from its most distant origin to its present stage; but a more extensive space than143the play of influences that have operated from one author to another, or than the domain of explicit polemics. Different œuvres, dispersed books, that whole mass of texts that belong to a single discursive formation — and so many authors who know or do not know one another, criticize one another, invalidate one another, pillage one another, meet without knowing it and obstinately intersect their unique discourses in a web of which they are not the masters, of which they cannot see the whole, and of whose breadth they have a very inadequate idea — all these various figures and individuals do not communicate solely by the logical succession of propositions that they advance, nor by the recurrence of themes, nor by the obstinacy of a meaning transmitted, forgotten, and rediscovered; they communicate by the form of positivity of their discourse, or more exactly, this form of positivity (and the conditions of operation of the enunciative function) defines a field in which formal identities, thematic continuities, translations of concepts, and polemical interchanges may be deployed. Thus positivity plays the role of what might be called a historical a priori.
