All in all, the analysis of the relationship between sign and meaning in Frege's logical symbolism shows that logical reasoning gains epistemological dignity only from the moment when it functions with the help of written signs to which one and only one meaning is attributed, in a given symbolic system. The lesson that results from this predilection for written signs to the detriment of oral signs is that of rigor, of the precision that must necessarily integrate the field of scientific knowledge. In Frege's logical symbolism, the written signs are more perfected than the oral signs and allow us to reach the highest level of knowledge, the level of pure knowledge, that which does not belong to the senses.