This paper explores various theories of curriculum intending to provide a new approach--which we regard as a significant theoretical contribution--to examine the broad set of different discourses that have been shaping science education. We first introduce concepts and values that support traditional and critical curriculum theories and offer some examples of international science education discourses that could be in tune with each of these approaches. We then develop a post-critical perspective (Laclau, Emancipação e diferença, EdUERJ, Rio de Janeiro, 2011) on curriculum, with emphasis on discourse theory (Laclau and Mouffe, Hegemonía y estrategia socialista: hacia uma radicalización de la democracia, Siglo XXI, Madrid, 1987) and on categories such as discourse, articulation, nodal points, antagonism and hegemony, to identify hegemonic and counter-hegemonic discourses in the scope of Brazilian science education scholarship and teacher education. Our analysis suggests that articulations and nodal points such as scientific knowledge, method and assessment have been framing traditional curriculum features that boost the hegemony of "knowledge itself." On the other hand, nodal points such as gender, society, nature, curriculum and power relations have been forging the critical curriculum perspective as a counter-hegemonic discourse in the struggle for the hegemony of "knowledge to do something." Nonetheless, more important than this portrait is the disclosure that antihegemonic discourses can support researchers who work for reactivating contingency and new antagonisms to transform science education.