We tend to imagine that if these newdomains were defined during the last century, it was simply that a slight increase in the objectivity of knowledge, in the precision of observation, in the rigour of our reasoning, in the organization of scientific research and information that all this, with the aid of a few fortunate discoveries, themselves helped by a little good luck or genius, enabled us to emerge from a prehistoric age in which knowledge was still stammering out the Grammaire de Port Royal, the classifications of Linnaeus, and the theories of trade or agriculture.