The requirement of assuming a given category of the true far the determination of the ideological -the
condition of true knowledge- has always been a basic premise of the classic theory of ideology. The
emergence of a "poststructuralist ethos", however, has meant the explicit denying of such condition,
becoming the main theoretical challenge to those authors who insist in using the notion of ideology in
"post moi:lern" times. This work assesses the classic answers given to the determination of the ideological
as well as the contemporary theories elaborated in response to the challenge posed by post-structuralism, ,
within the descriptive and negative research program on ideology distinguished by Geuss (1981). The
paper finally propases a re-conceptualisation of the notion of ideology which, acknowledging the permanence
of the 'necessity' of the true, places the praxis of the individuals as the main "locus" for both the ideological