Agency (sociology) experiences, and the perceptions held by the society and the individual, of the structures and circumstances of the environment one is in and the position they are born into. Disagreement on the extent of one's agency often causes conflict between parties, e.g. parents and children. The concept of agency has existed since the Enlightenment. René Descartes' phrase Cogito ergo sum stated that anyone who could think is an agent , and any agent capable of knowing that it can think was a subject. Immanuel Kant expanded on this theory by stating that the only way to truly become self-aware is
Cogito and the History of Madness translation of the text into English as "Madness and Civilization". The abridged 1964 edition removed the pages concerning Descartes on which Derrida had explicitly based his argument in "Cogito and the History of Madness." These pages on Descartes were only made available in English with Jean Khalfa's 2006 translation of Foucault's work on madness. Derrida makes an allusion to the master–slave dialectic in Hegel's "Phenomenology of Spirit" in the opening pages of "Cogito and the History of Madness." Foucault writes at the start of the second chapter of the "History of Madness" of a strange violent event that silenced madness