This chapter argues that no matter how hard the structuralists and post-structuralists try to avoid dealing with scientific dialectics, or as much as they merely reject it, their thinking still remains within the confines of dialectics. Following parallel lines of evolution, structuralism and poststructuralism relate to a phenomenological perspective on the sciences that intends to reveal a more rigorous science, which is achieved either a priori, as in Edmund Husserl, or a posteriori, as in ethnomethodology. The chapter shows that even if structures help the reader of epistemology to understand the scientific edifice, there can be no performative structure with dysfunctional or non-existent subjects of action. Furthermore, it addresses the implicit but remarkable 'anxiety' of structuralism and poststructuralism as far as the void of scientific elenchus is concerned. Poststructuralism attempts to address the previous deficit by prioritizing scientific reflexivity that produces accountability criteria for the sciences.