In the Classical period, the field of knowledge, from the project of an analysis of representation to the theme of the mathesis universalis, was perfectly homogeneous: all knowledge, of whatever kind, proceeded to the ordering of its material by the establishment of differences and defined those differences by the establishment of an order; this was true for mathematics, true also for taxonomies (in the broad sense) and for the sciences of nature; but it was equally true for all those approximative, imperfect, and largely spontaneous kinds of knowledge which are brought into play in the construction of the least fragment of discourse or in the daily processes of exchange; and it was true, finally, for philosophical thought and for those long chains of order that the 'Id ologues', no less than Descartes or Spinoza, though in a different way, attempted to establish in order to create a path leading necessarily from the very simplest and most evident of ideas to the most composite truths.