It is an easily recognizable feature of the way science is considered in our days that almost no educated person or scientist would claim that science is a true knowledge (an exception is sometimes made for mathematical disciplines, but their "truth" is in any case considered as a very special one and will therefore not be of our concern in the present paper). Such a general tendency not to mix truth with science does not express on the other hand any mistrust or underestimation of the science of our time; on the contrary, it has coincided with a growth of such an estimation up to the point that an equally general tendency is nowadays established to consider science as the model, as the "paradigm" of our knowledge, in the sense that every field of research in which "rigourous" knowledge is reached by respecting some accepted methodological requirements, is accepted to constitute a science.