This thesis develops an analysis of Brazilian public schools as institutions that can contribute towards the denmocratization of public space. The analysis considers that, for theoretical, ethical and political reasons, the plurality present in Brazilian society, and which manifests itself in its public schools, needs to make reference to the struggles for substantive equality. It is argued that, in the face of the profound social inequalities imposed by capital in its phase of global development, a rich comprehension of plurality can only be realized through the establishment of conditions of equality in social relations, looking towards the overcoming of socioeconomic injustices as well as the injustices that are products of lack of respect, lack of recognition and cultural domination. On the basis of this argument, the thesis develops a critical analysis of postmodern conceptions that appropriate concepts such as culture, identity and difference, without relating them to the struggles for an egalitarian, democratic and socialist society. At the same time, the dissertation emphasizes labour as an organising principle of plurality, because it potentializes the processes of individualization by its capacity to create culture, to form identities and to enunciate differences in ways of feeling, thinking and intervening in the world. The comprehension of labour as an organising principle of plurality confronts the Brazilian public school with the challenge to value the pedagogical relation between educator and educated and to overcome the internal mechanisms that inhibit school life, in order to make possible the appropriation and reappropriation of knowledge in the direction of human emancipation and social transformation.