We examine the role of the idea of necessity in scientific knowledge, in particular in contemporary sciences, taking into account the difficulty to invoke it as a principle for a knowledge considered as symbolic and built-up, with only an indirect access to the reality of the world. We propose here the thesis that, while keeping full consideration of the subject (of knowledge), the movement of science receives its meaning from immanence alone, and that its dynamics is given from necessity. Contemporary science, and particularly physics, support this view, considering how they evaluate the inherent limitations of theoretical systems of concepts, how they overcome and reorganize the latter (see for instance the role of invariance and symmetrie principles, or again the meaning of the criterium of «relative theoretical completeness »). Scientific knowledges are symbolic forms in the world that are themselves endowed with a temporal and evolutive dimension : they are submitted to proof in the time of history while being accompanied by a correlative modification of the structures of intelligibility, i.e. an adaptation of the conditions of possibility of knowledge to the immanent world. The contingent part of scientific knowledges as symbolic forms appears finally underground-oriented by the necessity of the world-matter.
Matter; Necessity; Contemporary science; Completeness; Imanency; Intelligibility