ABSTRACT
However, to a believer in discontinuity, the review of literature ought rather to serve to illustrate how opinions and concepts that have been and continue to be applied acquire their real meaning only at the moment when they appear, and how this appearance, in a majority of cases, does not respond to the needs of scientific knowledge but rather obeys and is a faithful reflection of political or ideological interests of the moment. By the same token, seen from the same perspective of discontinuity, the appearance of new, more operative formulations does not represent a mere addition to previous work. Rather, it implies the disappearance of other conceptions-though this is never total, since certain elements of prior frameworks may continue to be useful. It is this circumstance which justifies the survival of the historiographical model of cumulative knowledge, as well as the coexistence of viewpoints that sharply oppose-but in equal measure recognise-each other.
