In an era when familiar categories of identity are breaking down, an argument is made for using post-structuralist vocabulary to talk about ethical practical action in mathematics education. Using aspects of Foucault's post-structuralism, an explanation is offered of how mathematical identifications are tied to the social organization of power. An analysis of 2 everyday instances is provided to capture the oppressive conditions in which ordinary people involved in mathematics are engaged. Describing how systemic constraints become lived as individual dilemmas offers a way of understanding what we might do to effect change, and what we might do to produce tangible results. (Contains 1 footnote.)